Answer:
The answer is 3.48 seconds
Explanation:
The kinematic equation
y= y0+V0*t+1/2*a*(t*t)
-50=0+(0)t+1/2(-9.8)*(t*t)
t=3.194 seconds
During ribbons ball,
x=x0+ Vt+1/2*a*(t*t)
x= 0+(15)*(3.194)+1/2*(0)* (3.194*3.194)
x= 47.9157m
So, distance (D) = 100-47.9157= 52.084m
52.084m=0+15(t)+1/2*(0)(t*t)
t=52.084/15=3.472286= 3.48seconds
A force in the negative x-direction is applied for 27 ms to a 0.4 kg mass initially moving at 14 m/s in the x-direction. The force varies in magnitude and delivers an impulse with a magnitude of 32.4 N-s. What is the mass's velocity in the x-direction
Answer:
-67 m/s
Explanation:
We are given that
Mass of ball,m=0.4 kg
Initial speed,u=14 m/s
Impulse,I=-32.4 N-s
Time,t=27 ms=[tex]27\times 10^{-3} s[/tex]
We have to find the mass's velocity in the x- direction.
We know that
[tex]Impulse=mv-mu[/tex]
Substitute the values
[tex]-32.4=0.4v-0.4(14)[/tex]
[tex]-32.4+0.4(14)=0.4 v[/tex]
[tex]-26.8=0.4v[/tex]
[tex]v=\frac{-26.8}{0.4}=-67m/s[/tex]
A hockey puck on a frozen pond is given an initial speed of 20.0 m/s. If the puck always remains on the ice and slides 115 m before coming to rest, determine the coefficient of kinetic friction between the puck and ice.
Answer:
μ_k = 0.1773
Explanation:
We are given;
Initial velocity;u = 20 m/s
Final velocity;v = 0 m/s (since it comes to rest)
Distance before coming to rest;s = 115 m
Let's find the acceleration using Newton's second law of motion;
v² = u² + 2as
Making a the subject, we have;
a = (v² - u²)/2s
Plugging relevant values;
a = (0² - 20²)/(2 × 115)
a = -400/230
a = -1.739 m/s²
From the question, the only force acting on the puck in the x direction is the force of friction. Since friction always opposes motion, we see that:
F_k = −ma - - - (1)
We also know that F_k is defined by;
F_k = μ_k•N
Where;
μ_k is coefficient of kinetic friction
N is normal force which is (mg)
Since gravity acts in the negative direction, the normal force will be positive.
Thus;
F_k = μ_k•mg - - - (2)
where g is acceleration due to gravity.
Thus,equating equation 1 and 2,we have;
−ma = μ_k•mg
m will cancel out to give;
-a = μ_k•g
μ_k = -a/g
g has a constant value of 9.81 m/s², so;
μ_k = - (-1.739/9.81)
μ_k = 0.1773
The coefficient of kinetic friction between the hockey puck and ice is equal to 0.178
Given the following data:
Initial speed = 20 m/sFinal velocity = 0 m/s (since it came to rest)Distance = 115 mScientific data:
Acceleration due to gravity = 9.8 [tex]m/s^2[/tex]To determine the coefficient of kinetic friction between the hockey puck and ice:
First of all, we would calculate the acceleration of the hockey puck by using the third equation of motion.
[tex]V^2 = U^2 + 2aS\\\\0^2 =20^2 + 2a(115)\\\\-400=230a\\\\a=\frac{-400}{230}[/tex]
Acceleration, a = -1.74 [tex]m/s^2[/tex]
Note: The negative signs indicates that the hockey puck is slowing down or decelerating.
From Newton's Second Law of Motion, we have:
[tex]\sum F_x = F_k + F_n =0\\\\F_k =- F_n\\\\\mu mg =-ma\\\\\mu = \frac{-a}{g}\\\\\mu = \frac{-(-1.74)}{9.8}\\\\\mu = \frac{1.74}{9.8}[/tex]
Coefficient of kinetic friction = 0.178
Read more: https://brainly.com/question/13821217
A packing crate rests on a horizontal surface. It is acted on by three horizontal forces: 600 N to the left, 200 N to the right, and friction. The weight of the crate is 400 N. If the 600-N force is removed, the resultant force acting on the crate is:
Answer:
200 N.
It seems very difficult but it really is not, as the wording just makes it seem difficult.
We have a force of 600 N, a force of 200N, and friction. We're leaving the direction of the forces aside. The weight of the crate is 400N, but this is totally irrelevant, as it is the crate itself, and not a force acting upon it. Now we have 600N and 200N. Taking away the 600N simply leaves us with 200N.
A 2.4-kg ball falling vertically hits the floor with a speed of 2.5 m/s and rebounds with a speed of 1.5 m/s. What is the magnitude of the impulse exerted on the ball by the floor
Answer:
9.6 Ns
Explanation:
Note: From newton's second law of motion,
Impulse = change in momentum
I = m(v-u).................. Equation 1
Where I = impulse, m = mass of the ball, v = final velocity, u = initial velocity.
Given: m = 2.4 kg, v = 2.5 m/s, u = -1.5 m/s (rebounds)
Substitute into equation 1
I = 2.4[2.5-(-1.5)]
I = 2.4(2.5+1.5)
I = 2.4(4)
I = 9.6 Ns
The magnitude of impulse will be "9.6 Ns".
According to the question,
Mass,
m = 2.4 kgFinal velocity,
v = 2.5 m/sInitial velocity,
u = -1.5 m/sBy using Newton's 2nd law of motion, we get
→ Impulse, [tex]I = m(v-u)[/tex]
By substituting the values, we get
[tex]= 2.4[2.5-(1.5)][/tex]
[tex]= 2.4(2.5+1.5)[/tex]
[tex]= 2.4\times 4[/tex]
[tex]= 9.6 \ Ns[/tex]
Thus the above answer is right.
Learn more about Impulse here:
https://brainly.com/question/15495020
The exit nozzle in a jet engine receives air at 1200 K, 150 kPa with negligible kinetic energy. The exit pressure is 80 kPa, and the process is reversible and adiabatic. Use constant specific heat at 300 K to find the
Complete question:
The exit nozzle in a jet engine receives air at 1200 K, 150 kPa with negligible kinetic energy. The exit pressure is 80 kPa, and the process is reversible and adiabatic. Use constant specific heat at 300 K to find the exit velocity.
Answer:
The exit velocity is 629.41 m/s
Explanation:
Given;
initial temperature, T₁ = 1200K
initial pressure, P₁ = 150 kPa
final pressure, P₂ = 80 kPa
specific heat at 300 K, Cp = 1004 J/kgK
k = 1.4
Calculate final temperature;
[tex]T_2 = T_1(\frac{P_2}{P_1})^{\frac{k-1 }{k}[/tex]
k = 1.4
[tex]T_2 = T_1(\frac{P_2}{P_1})^{\frac{k-1 }{k}}\\\\T_2 = 1200(\frac{80}{150})^{\frac{1.4-1 }{1.4}}\\\\T_2 = 1002.714K[/tex]
Work done is given as;
[tex]W = \frac{1}{2} *m*(v_i^2 - v_e^2)[/tex]
inlet velocity is negligible;
[tex]v_e = \sqrt{\frac{2W}{m} } = \sqrt{2*C_p(T_1-T_2)} \\\\v_e = \sqrt{2*1004(1200-1002.714)}\\\\v_e = \sqrt{396150.288} \\\\v_e = 629.41 \ m/s[/tex]
Therefore, the exit velocity is 629.41 m/s
A place-kicker must kick a football from a point 36.0 m (about 40 yards) from the goal. Half the crowd hopes the ball will clear the crossbar, which is 3.05 m high. When kicked, the ball leaves the ground with a speed of 21.6 m/s at an angle of 50.0° to the horizontal.
Required:
By how much does the ball clear or fall short (vertically) of clearing the crossbar?
Answer:
The difference is height is [tex]\Delta h =6.92 \ m[/tex]
Explanation:
From the question we are told that
The distance of ball from the goal is [tex]d = 36.0 \ m[/tex]
The height of the crossbar is [tex]h = 3.05 \ m[/tex]
The speed of the ball is [tex]v = 21.6 \ m/s[/tex]
The angle at which the ball was kicked is [tex]\theta = 50 ^o[/tex]
The height attained by the ball is mathematically represented as
[tex]H = v_v * t - \frac{1}{2} gt^2[/tex]
Where [tex]v_v[/tex] is the vertical component of velocity which is mathematically represented as
[tex]v_v = v * sin (\theta )[/tex]
substituting values
[tex]v_v = 21.6 * (sin (50 ))[/tex]
[tex]v_v = 16.55 \ m/s[/tex]
Now the time taken is evaluated as
[tex]t = \frac{d}{v * cos(\theta )}[/tex]
substituting value
[tex]t = \frac{36}{21.6 * cos(50 )}[/tex]
[tex]t = 2.593 \ s[/tex]
So
[tex]H = 16.55 * 2.593 - \frac{1}{2} * 9.8 * (2.593)^3[/tex]
[tex]H = 9.97 \ m[/tex]
The difference in height is mathematically evaluated as
[tex]\Delta h = H - h[/tex]
substituting value
[tex]\Delta h = 9.97 - 3.05[/tex]
[tex]\Delta h =6.92 \ m[/tex]
An airplane flies between two points on the ground that are 500 km apart. The destination is directly north of the origination of the flight. The plane flies with an air speed of 120 m/s. If a constant wind blows at 10.0 m/s due west during the flight, what direction must the plane fly relative to north to arrive at the destination? Consider: east to the right, west to the left, north upwards and south downwards
Answer:
θ = 4.78º
with respect to the vertical or 4.78 to the east - north
Explanation:
This is a velocity compound exercise since it is a vector quantity.
The plane takes a direction, the air blows to the west and the result must be to the north, let's use the Pythagorean theorem to find the speed
v_fly² = v_nort² + v_air²
v_nort² = v_fly² + - v_air²
Let's use trigonometry to find the direction of the plane
sin θ = v_air / v_fly
θ = sin⁻¹ (v_air / v_fly)
let's calculate
θ = sin⁻¹ (10/120)
θ = 4.78º
with respect to the vertical or 4.78 to the north-east
New evidence increasingly emphasizes that __________.
Three blocks are placed in contact on a horizontal frictionless surface. A constant force of magnitude F is applied to the box of mass M. There is friction between the surfaces of blocks 2M and 3M so the three blocks accelerate together to the right.
Which block has the smallest net force acting on it?
A) M
B) 2M
C) 3M
D) The net force is the same for all three blocks Submit
Answer:
A) M
Explanation:
The three blocks are set in series on a horizontal frictionless surface, whose mutual contact accelerates all system to the same value due to internal forces as response to external force exerted on the box of mass M (Newton's Third Law). Let be F the external force, and F' and F'' the internal forces between boxes of masses M and 2M, as well as between boxes of masses 2M and 3M. The equations of equilibrium of each box are described below:
Box with mass M
[tex]\Sigma F = F - F' = M\cdot a[/tex]
Box with mass 2M
[tex]\Sigma F = F' - F'' = 2\cdot M \cdot a[/tex]
Box with mass 3M
[tex]\Sigma F = F'' = 3\cdot M \cdot a[/tex]
On the third equation, acceleration can be modelled in terms of F'':
[tex]a = \frac{F''}{3\cdot M}[/tex]
An expression for F' can be deducted from the second equation by replacing F'' and clearing the respective variable.
[tex]F' = 2\cdot M \cdot a + F''[/tex]
[tex]F' = 2\cdot M \cdot \left(\frac{F''}{3\cdot M} \right) + F''[/tex]
[tex]F' = \frac{5}{3}\cdot F''[/tex]
Finally, F'' can be calculated in terms of the external force by replacing F' on the first equation:
[tex]F - \frac{5}{3}\cdot F'' = M \cdot \left(\frac{F''}{3\cdot M} \right)[/tex]
[tex]F = \frac{5}{3} \cdot F'' + \frac{1}{3}\cdot F''[/tex]
[tex]F = 2\cdot F''[/tex]
[tex]F'' = \frac{1}{2}\cdot F[/tex]
Afterwards, F' as function of the external force can be obtained by direct substitution:
[tex]F' = \frac{5}{6}\cdot F[/tex]
The net forces of each block are now calculated:
Box with mass M
[tex]M\cdot a = F - \frac{5}{6}\cdot F[/tex]
[tex]M\cdot a = \frac{1}{6}\cdot F[/tex]
Box with mass 2M
[tex]2\cdot M\cdot a = \frac{5}{6}\cdot F - \frac{1}{2}\cdot F[/tex]
[tex]2\cdot M \cdot a = \frac{1}{3}\cdot F[/tex]
Box with mass 3M
[tex]3\cdot M \cdot a = \frac{1}{2}\cdot F[/tex]
As a conclusion, the box with mass M experiments the smallest net force acting on it, which corresponds with answer A.
If a car stops suddenly, you feel "thrown forward." We'd like to understand what happens to the passengers as a car stops. Imagine yourself sitting on a very slippery bench inside a car. This bench has no friction, no seat back, and there's nothing for you to hold on to.
A. Draw a picture and identify all of the forces action on you as thecar travels at a perfectly steady speed on level ground.
B. Draw your free-body diagram. Is there a net force on you?
C. Describe what happens to you as the car slowsdown?
D. Suppose now that the bench is not slippery. As the carslows down, you stay on the bench and dont slide off. What force is responsible for you deceleration?
E. In which directin does this froce point?
Answer:
a. i. applied force
ii. gravitational force
iii. normal force of reaction
b. net force is zero
c. we move forward
d. frictional force
e. opposite dirction of force applied
Explanation:
How many diffraction maxima are contained in a region of the Fraunhofer single-slit pattern, subtending an angle of 2.12°, for a slit width of 0.110 mm, using light of wavelength 582 nm?
Answer:
6
Explanation:
We are given that
[tex]\theta=2.12^{\circ}[/tex]
Slid width,a=0.110 mm=[tex]0.11\times 10^{-3} m[/tex]
[tex]1mm=10^{-3} m[/tex]
Wavelength,[tex]\lambda=582 nm=582\times 10^{-9}[/tex] m
[tex]1nm=10^{-9} m[/tex]
We have to find the number of diffraction maxima are contained in a region of the Fraunhofer single-slit pattern.
[tex]asin\theta=\frac{2N+1}{2}\lambda[/tex]
Using the formula
[tex]0.11\times 10^{-3}sin(2.12)=\frac{2N+1}{2}(582\times 10^{-9})[/tex]
[tex]2N+1=\frac{0.11\times 10^{-3}sin(2.12)\times 2}{582\times 10^{-9}}[/tex]
[tex]2N+1=13.98[/tex]
[tex]2N=13.98-1=12.98[/tex]
[tex]N=\frac{12.98}{2}\approx 6[/tex]
Hence, 6 diffraction maxima are contained in a region of the Fraunhofer single-slit pattern
The index of refraction for a certain type of glass is 1.645 for blue light and 1.609 for red light. A beam of white light (one that contains all colors) enters a plate of glass from the air, nair≈1, at an incidence angle of 38.55∘. What is the absolute value of ????, the angle in the glass between blue and red parts of the refracted beams?
Answer:
blue θ₂ = 22.26º
red θ₂ = 22.79º
Explanation:
When a light beam passes from one material medium to another, it undergoes a deviation from the path, described by the law of refraction
n₁ sin θ₁ = n₂ sin θ₂
where n₁ and n₂ are the incident and transmitted media refractive indices and θ are the angles in the media
let's apply this equation to each wavelength
λ = blue
in this case n₁ = 1, n₂ = 1,645
sin θ₂ = n₁/ n₂ sin₂ θ₁
let's calculate
sin θ₂ = 1 / 1,645 sint 38.55
sin θ₂ = 0.37884
θ₂ = sin⁻¹ 0.37884
θ₂ = 22.26º
λ = red
n₂ = 1,609
sin θ₂ = 1 / 1,609 sin 38.55
sin θ₂ = 0.3873
θ₂ = sim⁻¹ 0.3873
θ₂ = 22.79º
the refracted rays are between these two angles
An object with a mass m slides down a rough 37° inclined plane where the coefficient of kinetic friction is 0.20. If the plane is 10 m long and the mass starts from rest, what will be its speed at the bottom of the plane?
Answer: 9.312 m/s
Explanation:
The friction force (opposite to the motion) is Fa = μ*m*g*cos(α) with μ = kinetic friction. The force that makes the motion is
F = m*g*sin(α).
The Newton's law gives:
F - Fa = m*a
m*g*sin(α) - μ*m*g*cos(α) = m*a
g*sin(α) - μ*g*cos(α) = a so a = 4.335 m/s²
It's a uniformly accelerated motion:
Space
S = 0.5*a*t²
10 = 0.5*a*t²
=> t = 2.148 s
Velocity
V = a*t = 9.312 m/s.
We have that the speed at the bottom of the plane is
[tex]v-9.3m/s[/tex]
From the question we are told that:
Angle of slide [tex]\theta =3.7 \textdegree[/tex]
Coefficient of kinetic friction [tex]\mu= 0.20[/tex]
Length [tex]L=10m[/tex]
Generally, the equation for acceleration along the slide is mathematically given by
[tex]a=gsin \theta-\mu cos\theta[/tex]
[tex]a=(9.8sin37-0.20*9.8*cos37[/tex]
[tex]a=4.33m/s^2[/tex]
Therefore
Velocity v is is mathematically given by
[tex]v=\sqrt{2as}[/tex]
[tex]v=\sqrt{2*4.33*10}[/tex]
[tex]v-9.3m/s[/tex]
In conclusion
The speed at the bottom of the plane is
[tex]v-9.3m/s[/tex]
For more information on this visit
https://brainly.com/question/16948127
Select the correct answer. When waves travel through water, why do the moving water particles continue to return to their starting position? A. Waves transfer matter, but not energy. B. Waves transfer both matter and energy. C. Waves transfer energy, but not matter. D. Waves don’t transfer matter or energy.
Waves transfer energy, but not matter. (C)
Answer:
C. Waves transfer energy not matter
Explanation:
wave is a disturbance
circular saw blade of diameter 0.190 m starts from rest. In a time interval of 5.80 s it accelerates with constant angular acceleration to an angular velocity of 145 rad/s. Part A Find the angular acceleration. Express your answer in radians per second squared. α = nothing rad/s2 Request Answer Part B Find the angle through which the blade has turned. Express your answer in radians. θ = nothing rad Request Answer Provide Feedback
Answer:
Explanation:
We shall apply newton's law equation valid for rotational motion .
ωt = ω₀ + α t where ωt is angular velocity after time t , ω₀ is angular velocity at t= 0 and α is angular acceleration
145 = 0 + α x 5.8
α = 25 rad / s²
B )
θ = ω₀ t + 1/2 α t²
= 0 + .5 x 25 x 5.8 x 5.8
= 420.5 rad .
Fiber optics are an important part of our modern internet. In these fibers, two different glasses are used to confine the light by total internal reflection at the critical angle for the interface between the core (ncore =1.497) and the cladding (ncladding =1.421)
Complete Question
The complete question is shown on the first uploaded image
Answer:
a
[tex]\theta_{max} =18.38^o[/tex]
b
New [tex]n_{cladding} =1.491[/tex]
Explanation:
From the question we are told that
The refractive index of the core is [tex]n_{core} = 1.497[/tex]
The refractive index of the cladding is [tex]n_{cladding} = 1.421[/tex]
Generally according to Snell's law
[tex]n_{core} * sin(90- \theta) = n_{cladding} * sin (90)[/tex]
Where [tex]\theta_{max}[/tex] is the largest angle a largest angle a ray will make with respect to the interface of the fiber and experience total internal reflection
[tex]\theta_{max} = 90 - sin^{-1} [\frac{n_{cladding}}{n_{core}} ][/tex]
[tex]\theta_{max} = 90 - sin^{-1} [\frac{1.421}{1.497}} ][/tex]
[tex]\theta_{max} =18.38^o[/tex]
Given from the question the the largest angle is 5°
Generally the refraction index of the cladding is mathematically represented as
[tex]n_{cladding} = n_{core} * sin (90 - 5)[/tex]
[tex]n_{cladding} =1.491[/tex]
A hockey puck slides off the edge of a horizontal platform with an initial velocity of 28.0 m/shorizontally in a city where the acceleration due to gravity is 9.81 m/s 2. The puck experiences no significant air resistance as it falls. The height of the platform above the ground is 2.00 m. What is the angle below the horizontal of the velocity of the puck just before it hits the ground
Answer:
θ = 12.60°
Explanation:
In order to calculate the angle below the horizontal for the velocity of the hockey puck, you need to calculate both x and y component of the velocity of the puck, and also you need to use the following formula:
[tex]\theta=tan^{-1}(\frac{v_y}{v_x})[/tex] (1)
θ: angle below he horizontal
vy: y component of the velocity just after the puck hits the ground
vx: x component of the velocity
The x component of the velocity is constant in the complete trajectory and is calculated by using the following formula:
[tex]v_x=v_o[/tex]
vo: initial velocity = 28.0 m/s
The y component is calculated with the following equation:
[tex]v_y^2=v_{oy}^2+2gy[/tex] (2)
voy: vertical component of the initial velocity = 0m/s
g: gravitational acceleration = 9.8 m/s^2
y: height
You solve the equation (2) for vy and replace the values of the parameters:
[tex]v_y=\sqrt{2gy}=\sqrt{2(9.8m/s^2)(2.00m)}=6.26\frac{m}{s}[/tex]
Finally, you use the equation (1) to find the angle:
[tex]\theta=tan^{-1}(\frac{6.26m/s}{28.0m/s})=12.60\°[/tex]
The angle below the horizontal is 12.60°
The angle below the horizontal of the velocity of the puck just before it hits the ground is 12.60°.
Given the following data:
Initial velocity = 28.0 m/s Acceleration due to gravity = 9.81 [tex]m/s^2[/tex]Displacement (height) = 2.00 meters.To find the angle below the horizontal of the velocity of the puck just before it hits the ground:
First of all, we would determine the horizontal and vertical components of the hockey puck.
For horizontal component:
[tex]V_y^2 = U_y^2 + 2aS\\\\V_y^2 = 0^2 + 2(9.81)(2)\\\\V_y^2 = 39.24\\\\V_y = \sqrt{39.24} \\\\V_y = 6.26 \; m/s[/tex]
For vertical component:
[tex]V_x = U_x\\\\V_x = 28.0 \;m/s[/tex]
Now, we can find the angle by using the formula:
[tex]\Theta = tan^{-1} (\frac{V_y}{V_x} )[/tex]
Substituting the values, we have:
[tex]\Theta = tan^{-1} (\frac{6.26}{28.0} )\\\\\Theta = tan^{-1} (0.2236)\\\\\Theta = 12.60[/tex]
Angle = 12.60 degrees.
Read more: https://brainly.com/question/8898885
In cricket how bowler and batsman use acceleration?
A total charge of 62 nC is uniformly distributed throughout a non-conducting sphere with a radius of 5.00 cm. The electric potential at r = 15.0 cm , relative to the potential far away, is:________
Answer:
2790 J/C
Explanation:
charge on sphere Q = 62 nC = [tex]62*10^{-9} C[/tex]
radius of the sphere r = 5.0 cm = 0.05 m
distance away from reference point d = 15.0 cm = 0.15 m
total distance of charge relative reference point R = r + d = 0.05 + 0.15 = 0.2 m
electric potential V is given as
[tex]V = \frac{kQ}{R}[/tex]
where k = Coulumb's constant = [tex]9*10^{9}[/tex] kg⋅m³⋅s⁻⁴⋅A⁻²
[tex]V = \frac{9*10^{9} * 62*10^{-9} }{0.2}[/tex] = [tex]\frac{9*62}{0.2}[/tex]
V = 2790 J/C
charged particles from the solar winds ultimately cause ___. a. the earth to maintain it's magnetic field b. the earth to change shape c. the auroras d. strong winds on earth
Answer:
The auroras C.
Explanation:
Suppose that when you move the north pole of a bar magnetic toward a coil it induces a positive current in the coil. The strength of the field produced by an electromagnetic can be controlled electronically. Suppose you place a coil near the north pole of an electromagnet and increase the field while keeping everything stationary. Which one of the following will happen? a) A positive current will be induced in the coilb) A negative current will be induced in the coil c) No current will be induced in the coil since there is no relative motion.
Answer:
a) A positive current will be induced in the coil
Explanation:
Electromagnetic induction is the induction of an electric field on a conductor due to a changing magnetic field flux. The change in the flux can be by moving the magnet relative to the conductor, or by changing the intensity of the magnetic field of the magnet. In the case of this electromagnets, the gradual increase in the the electromagnet's field strength will cause a flux change, which will in turn induce an electric current on the coil.
According to Lenz law, the induced current acts in such a way as to negate the motion or action that is producing it. A positive current will be induced on the coil so as to repel any form of attraction between the north pole of the electromagnet and the coil. This law obeys the law of conservation of energy, since work has to be done to move the move them closer to themselves.
Robin is standing terrified at the end of a diving board, which is high above the water. If Robin has a mass of 76 kg and is standing 1.6 m from the board's pivot point, what torque is Robin exerting on the board
Answer:
Torque = 1191.68 N-m
Explanation:
Given data
mass m = 76 kg
standingdistance r = 1.6 m
Solution
we get here torque that si express as
torque = force × distance ................1
torque = r × F sin(theta)
and we know that
F = mg .........2
and g = 9.8 m/s²
put here value in equation 1 we get
Torque = 76 × 1.6 × 9.8 × sin(90)
Torque = 1191.68 N-m
Assume you have a rocket in Earth orbit and want to go to Mars. The required change in velocity is ΔV≈9.6km/s . There are two options for the propulsion system --- chemical and electric --- each with a different specific impulse. Recall that the relationship between specific impulse and exhaust velocity is: Vex=g0Isp Using the Ideal Rocket Equation and setting g0=9.81m/s2 , calculate the propellant fraction required to achieve the necessary ΔV for each of propulsion system. Part 1: Cryogenic Chemical Propulsion First, consider a cryogenic chemical propulsion system with Isp≈450s . Enter the required propellant fraction as a proportion with at least 2 decimal places (i.e., enter 0.25 to represent 25%): incorrect Part 2: Electric Propulsion Next, consider an electric propulsion system with Isp≈2000s . Enter the required propellant fraction as a proportion with at least 2 decimal places (i.e., enter 0.25 to represent 25%):
Answer: Part 1: Propellant Fraction (MR) = 8.76
Part 2: Propellant Fraction (MR) = 1.63
Explanation: The Ideal Rocket Equation is given by:
Δv = [tex]v_{ex}.ln(\frac{m_{f}}{m_{e}} )[/tex]
Where:
[tex]v_{ex}[/tex] is relationship between exhaust velocity and specific impulse
[tex]\frac{m_{f}}{m_{e}}[/tex] is the porpellant fraction, also written as MR.
The relationship [tex]v_{ex}[/tex] is: [tex]v_{ex} = g_{0}.Isp[/tex]
To determine the fraction:
Δv = [tex]v_{ex}.ln(\frac{m_{f}}{m_{e}} )[/tex]
[tex]ln(MR) = \frac{v}{v_{ex}}[/tex]
Knowing that change in velocity is Δv = 9.6km/s and [tex]g_{0}[/tex] = 9.81m/s²
Note: Velocity and gravity have different measures, so to cancel them out, transform km in m by multiplying velocity by 10³.
Part 1: Isp = 450s
[tex]ln(MR) = \frac{v}{v_{ex}}[/tex]
ln(MR) = [tex]\frac{9.6.10^{3}}{9.81.450}[/tex]
ln (MR) = 2.17
MR = [tex]e^{2.17}[/tex]
MR = 8.76
Part 2: Isp = 2000s
[tex]ln(MR) = \frac{v}{v_{ex}}[/tex]
ln (MR) = [tex]\frac{9.6.10^{3}}{9.81.2.10^{3}}[/tex]
ln (MR) = 0.49
MR = [tex]e^{0.49}[/tex]
MR = 1.63
A block of mass M rests on a block of mass M1 which is on a tabletop. A light string passes over a frictionless peg and connects the blocks. The coefficient of kinetic friction between the blocks and between M1 and the tabletop is the same. A force F pulls the upper block to the left and the lower block to the right. The blocks are moving at a constant speed. Required:Determine the mass of the upper block. (Express your answer to three significant figures.)
Answer:
M = 3.66 kg
Explanation:
Here is the complete question
A block of mass M rests on a block of mass M1 = 5.00 kg which is on a tabletop. A light string passes over a frictionless peg and connects the blocks. The coefficient of kinetic friction μ
k at both surfaces equals 0.330. A force of F = 56.0 N pulls the upper block to the left and the lower block to the right. The blocks are moving at a constant speed. Determine the mass of the upper block. (Express your answer to three significant figures.)
Solution
The forces on mass M are
F - μMg = Ma (1)
The forces on mass M₁ are
F - μ(M + M₁)g = M₁a (2) (since both weights act downwards on M)
From (1) a = (F - μMg)/M
Substituting a into (2), we have
F - μ(M + M₁)g = M₁((F - μMg)/M)
Cross-multiplying M we have
MF - μ(M + M₁)Mg = M₁F - μMM₁g
Expanding the bracket, we have
MF - μM²g + μM₁Mg = M₁F - μMM₁g
We now collect like terms
MF - μM²g + μM₁Mg + μMM₁g = M₁F
MF - μM²g + 2μM₁Mg - M₁F = 0
- μM²g + 2μM₁Mg + MF - M₁F = 0
Dividing through by -1, we have
- μM²g + (2μM₁g + F)M - M₁F = 0
μM²g - (2μM₁g + F)M + M₁F = 0
M² - (2M₁ + F/μg)M + M₁F/μg = 0
We now have a quadratic equation in M. We now substitute the values of the variables int o the quadratic equation to get
M² - (2(5 kg) + 56 N/(0.33 × 9.8 m/s²))M + (5 kg × 56 N)/(0.33 × 9.8 m/s²) = 0
M² - (10 kg) + 56 N/3.234 m/s²)M + (5 kg × 56 N)/(3.234 m/s²) = 0
M² - (10 kg + 17.32 kg) M + 86.58 kg = 0
M² - 27.32 kg M + 86.58 kg = 0
Using the quadratic formula
with a = 1, b = -27.32 and c = 86.58,
[tex]M = \frac{-(-27.32) +/- \sqrt{(-27.32)^{2} - 4 X 1 X 86.58} }{2 X 1} \\= \frac{27.32 +/- \sqrt{746.38 - 346.32} }{2}\\= \frac{27.32 +/- \sqrt{400.06} }{2}\\= \frac{27.32 +/- 20.001 }{2}\\= \frac{27.32 + 20.001 }{2} or \frac{27.32 - 20.001 }{2}\\= \frac{47.32 }{2} or \frac{7.32 }{2}\\\\=23.66 or 3.66[/tex]
Since M cannot be greater than M₁ for M to move over M₁, we take the smaller number.
So, M = 3.66 kg
An electron moving in a direction perpendicular to a uniform magnetic field at a speed of 1.6 107 m/s undergoes an acceleration of 7.0 1016 m/s2 to the right (the positive x-direction) when its velocity is upward (the positive y-direction). Determine the magnitude and direction of the field.
Answer:
B = 0.024T positive z-direction
Explanation:
In this case you consider that the direction of the motion of the electron, and the direction of the magnetic field are perpendicular.
The magnitude of the magnetic force exerted on the electron is given by the following formula:
[tex]F=qvB[/tex] (1)
q: charge of the electron = 1.6*10^-19 C
v: speed of the electron = 1.6*10^7 m/s
B: magnitude of the magnetic field = ?
By the Newton second law you also have that the magnetic force is equal to:
[tex]F=qvB=ma[/tex] (2)
m: mass of the electron = 9.1*10^-31 kg
a: acceleration of the electron = 7.0*10^16 m/s^2
You solve for B from the equation (2):
[tex]B=\frac{ma}{qv}\\\\B=\frac{(9.1*10^{-31}kg)(7.0*10^{16}m/s^2)}{(1.6*10^{-19}C)(1.6*10^7m/s)}\\\\B=0.024T[/tex]
The direction of the magnetic field is found by using the right hand rule.
The electron moves upward (+^j). To obtain a magnetic forces points to the positive x-direction (+^i), the direction of the magnetic field has to be to the positive z-direction (^k). In fact, you have:
-^j X ^i = ^k
Where the minus sign of the ^j is because of the negative charge of the electron.
Then, the magnitude of the magnetic field is 0.024T and its direction is in the positive z-direction
An electron moves at a speed of 1.0 x 104 m/s in a circular path of radius 2 cm inside a solenoid. The magnetic field of the solenoid is perpendicular to the plane of the electron’s path. Calculate (a) the strength of the magnetic field inside the solenoid and (b) the current in the solenoid if it has 25 turns per centimeter.
Answer:
(a) B = 2.85 × [tex]10^{-6}[/tex] Tesla
(b) I = I = 0.285 A
Explanation:
a. The strength of magnetic field, B, in a solenoid is determined by;
r = [tex]\frac{mv}{qB}[/tex]
⇒ B = [tex]\frac{mv}{qr}[/tex]
Where: r is the radius, m is the mass of the electron, v is its velocity, q is the charge on the electron and B is the magnetic field
B = [tex]\frac{9.11*10^{-31*1.0*10^{4} } }{1.6*10^{-19}*0.02 }[/tex]
= [tex]\frac{9.11*10^{-27} }{3.2*10^{-21} }[/tex]
B = 2.85 × [tex]10^{-6}[/tex] Tesla
b. Given that; N/L = 25 turns per centimetre, then the current, I, can be determined by;
B = μ I N/L
⇒ I = B ÷ μN/L
where B is the magnetic field, μ is the permeability of free space = 4.0 ×[tex]10^{-7}[/tex]Tm/A, N/L is the number of turns per length.
I = B ÷ μN/L
= [tex]\frac{2.85*10^{-6} }{4*10^{-7} *25}[/tex]
I = 0.285 A
According to Oxford Dictionaries, a spit take is an act of suddenly spitting out liquid one is drinking in response to something funny or surprising. In spit takes, a gauge pressure is applied in the mouth, p1, so that liquid flows through pursed lips forming a column of liquid with radius r2 = 4 mm. If the liquid travels at v2 = 3.1 m/s outside the body, and if the column's area is 10x larger inside the mouth, what is p1 in Pa?
Answer:
The pressure is [tex]p_1 = 4051.4 \ Pa[/tex]
Explanation:
From the question we are told that
The gauge pressure at the mouth is [tex]p_1[/tex]
The radius of the column is [tex]r_2 = 4 \ mm = 0.004 \ m[/tex]
The speed of the liquid outside the body is [tex]v_2 = 3.1 \ m/s[/tex]
The area of the column is [tex]A_2[/tex]
The area inside the mouth [tex]A_1 = 10 A_2[/tex]
Generally according to continuity equation
[tex]v_1 A_1 = v_2 A_2[/tex]
=> [tex]v_ 1 = v_2 * \frac{A_2}{A_1}[/tex]
=> [tex]v_ 1 = 3.1 * \frac{1}{10}[/tex]
=> [tex]v_ 1 = 0.31 \ m/s[/tex]
So
[tex]A_1 = 10A_2[/tex]
=> [tex]\pi * r_1^2 = 10(\pi * r_2^2)[/tex]
=> [tex]r_1 = 10 * r_2[/tex]
substituting values
[tex]r_1 = 10 * 0.004[/tex]
[tex]r_1 =0.04 \ m[/tex]
Now the height of inside the mouth is [tex]h_1 = d = 2r_1 = 2* 0.04 = 0.08\ m[/tex]
Now the height of the column is [tex]h_2 = d = 2r_2 = 2* 0.004 = 0.008\ m[/tex]
Generally according to Bernoulli's equation
[tex]p_1 = [\frac{1}{2} \rho v_2^2 + h_2 \rho g +p_2] -[\frac{1}{2} \rho * v_1^2 + h_1 \rho g ][/tex]
Now [tex]\rho = 1000 \ kg m^{-3}[/tex] which is the density of water
[tex]p_2[/tex] is the gauge pressure of the atmosphere which is zero
So
[tex]p_1 = [(0.5 * 1000 * (3.1)^2) +(0.008 * 1000 * 9.8) + 0]-[/tex]
[tex][(0.5 * 1000 * 0.31^2) + (0.08*1000 * 9.8)][/tex]
[tex]p_1 = 4051.4 \ Pa[/tex]
The initial pressure of the gauge pressure at the mouth is 4757 pascals.
The principle of continuity equation asserts that in a steady flow state, the quantity of fluid flowing at the inlet is equivalent to the quantity of fluid at the outlet given that there is a constant mass flow rate.
It can be expressed by using the formula:
[tex]\mathbf{A_1v_1=A_2v_2}[/tex]
where;
The speed of the liquid inside the body is [tex]\mathbf{v_1}[/tex] = ???The speed of the liquid outside the body is [tex]\mathbf{v_2}[/tex] = 3.1 m/sArea outside the column is = A₂Area inside the column is [tex]\mathbf{A_1}[/tex] = 10A₂∴
Making v₁ the subject of the formula:
[tex]\mathbf{v_1 = \dfrac{A_2}{A_1}\times v_2}[/tex]
[tex]\mathbf{v_1 = \dfrac{1}{10}\times3.1}[/tex]
[tex]\mathbf{v_1 =0.31 \ m/s}[/tex]
Since the area are equivalent to each other
[tex]\mathbf{A_1 = 10A_2}[/tex]
[tex]\mathbf{\pi r^2_1 = 10\times \pi r^2_2}[/tex]
[tex]\mathbf{ r^2_1 = 10\times r^2_2}[/tex]
where;
r₂ = radius of the column. = 4mm = 0.004 m∴
[tex]\mathbf{ r_1 = 10\times 0.004}[/tex]
[tex]\mathbf{ r^2_1 = 0.04 \ m}[/tex]
However, in fluid dynamics, Bernoulli's equation can be applied for the estimation of the initial gauge pressure by using the expression:
[tex]\mathbf{\dfrac{1}{2} \rho v_1^2 + h_1 \rho g + p_1 = \dfrac{1}{2}\rhov_2^2 + h_2 \rho g +p_2}[/tex]
Since the gauge pressure of the atmosphere [tex]\mathbf{p_2}[/tex] = 0
∴
The initial gauge pressure applied at the mouth can be determined as:
[tex]\mathbf{p_1 = \dfrac{1}{2} \rho ( v_2^2-v_1^2)}[/tex]
here;
[tex]\mathbf{\rho = 1000 \ kg/m^3}[/tex]
[tex]\mathbf{p_1 = \dfrac{1}{2} \times 1000 \ kg/m^3 ( 3.1^2-0.31^2)}[/tex]
[tex]\mathbf{p_1 =500 \ kg/m^3 (9.5139)}[/tex]
[tex]\mathbf{p_1 =4756.95 \ Pa}[/tex]
[tex]\mathbf{p_1 \simeq4757 \ Pa}[/tex]
Learn more about the principle of continuity equation here:
https://brainly.com/question/14619396
A car travels 13 km in a southeast direction and then 16 km 40 degrees north of east. What is the car's resultant direction?
Answer:
21.48 km 2.92° north of east
Explanation:
To find the resultant direction, we need to calculate a sum of vectors.
The first vector has module = 13 and angle = 315° (south = 270° and east = 360°, so southeast = (360+270)/2 = 315°)
The second vector has module 16 and angle = 40°
Now we need to decompose both vectors in their horizontal and vertical component:
horizontal component of first vector: 13 * cos(315) = 9.1924
vertical component of first vector: 13 * sin(315) = -9.1924
horizontal component of second vector: 16 * cos(40) = 12.2567
vertical component of second vector: 16 * sin(40) = 10.2846
Now we need to sum the horizontal components and the vertical components:
horizontal component of resultant vector: 9.1924 + 12.2567 = 21.4491
vertical component of resultant vector: -9.1924 + 10.2846 = 1.0922
Going back to the polar form, we have:
[tex]module = \sqrt{horizontal^2 + vertical^2}[/tex]
[tex]module = \sqrt{460.0639 + 1.1929}[/tex]
[tex]module = 21.4769[/tex]
[tex]angle = arc\ tangent(vertical/horizontal)[/tex]
[tex]angle = arc\ tangent(1.0922/21.4491)[/tex]
[tex]angle = 2.915\°[/tex]
So the resultant direction is 21.48 km 2.92° north of east.
How much electrical energy is used by a 75 W laptop that is operating for 12
minutes?
"1 watt" means 1 joule of energy per second.
75 W means 75 joules/sec .
Energy = (75 Joule/sec) x (12 min) x (60 sec/min)
Energy = (75 x 12 x 60) (Joule-min-sec / sec-min)
Energy = 54,000 Joules
Egocentrism exists during which of Piaget's stages?
sensorimotor
preoperational
concrete operations
formal operations
Answeri believe it is the first one but not sure
Explanation:
Answer:
The answer is sensorimotor.
Explanation: