Answer:
The torque on the child is now the same, τ.
Explanation:
It can be showed that the external torque applied by a net force on a rigid body, is equal to the product of the moment of inertia of the body with respect to the axis of rotation, times the angular acceleration.In this case, as the movement of the child doesn't create an external torque, the torque must remain the same.The moment of inertia is the sum of the moment of inertia of the merry-go-round (the same that for a solid disk) plus the product of the mass of the child times the square of the distance to the center.When the child is standing at the edge of the merry-go-round, the moment of inertia is as follows:[tex]I_{to} = I_{d} + m*r^{2} = m*\frac{r^{2}}{2} + m*r^{2} = \frac{3}{2}* m*r^{2} (1)[/tex]
So, τ = 3/2*m*r²*α (2)When the child moves to a position half way between the center and the edge of the merry-go-round, the moment of inertia of the child decreases, as the distance to the center is less than before, as follows:[tex]I_{t} = I_{d} + m*\frac{r^{2}}{4} = m*\frac{r^{2}}{2} + m*\frac{r^{2}}{4} = \frac{3}{4}* m*r^{2} (3)[/tex]
Since the angular acceleration increases from α to 2*α, we can write the torque expression as follows:τ = 3/4*m*r² * (2α) = 3/2*m*r²
same result than in (2), so the torque remains the same.
The wavelength of a water wave is 54 m. It has a frequency of 0.03 Hz. What is the velocity of the wave?
Answer:
1.62 m/s
Explanation:
Wavelength of the water wave= 54 m
The frequency is 0.03 Hz
Therefore the velocity can be calculated as follows
Velocity= frequency × wavelength
= 0.03 × 54
= 1.62 m/s
Suppose three forces are acting on a model rocket launching into the air. The force of gravity is 1.2 N acting downward. The rocket engine has a force of 12.3 N acting at an angle of 65⁰ above the horizontal to the right. The wind pushes the rocket with a force of 2.5 N to the left. Find the magnitude and direction of the resultant force on the rocket.
Please answer!!! Offering 50 points for answer and explanation
Answer:
can you include a picture
Decompose the forces acting on the rocket in horizontal and vertical components.
• net horizontal force:
∑ F = (12.3 N) cos(65°) - 2.5 N ≈ 2.7 N
(notice we're taking "to the right" to be the positive direction)
• net vertical force:
∑ F = (12.3 N) sin(65°) - 1.2 N ≈ 9.9 N
The resultant force then has magnitude
√((2.7 N)² + (9.9 N)²) ≈ 10.3 N
Since the horizontal and vertical components of the resultant are both positive, it points at an angle between 0° and 90° from the positive horizontal, so that
tan(θ) ≈ (9.9 N) / (2.7 N) ≈ 3.69
===> θ ≈ arctan(3.69) ≈ 75°
One of the two rectangular components of a force is 20N and it makes an angle of 30
with the force. Find the magnitude of the other components.
Answer:
11.545NExplanation:
The the horizontal and vertical component be expressed as;
Fx = Fxos theta (horizontal compt)
Given Fx = 20N
theta = 30°
Get F:
20 = Fcos30
20 = 0.8660F
F = 20/0.8660
F = 23.09N
Get the magnitude of the other components. (vertical compt)
Fy = Fsin theta
Fy = 23.09sin30
Fy = 23.09(0.5)
Fy = 11.545N
Hence the magnitude of the other component is 11.545N
A truck is traveling at 27 m/s down the interstate highway where you are changing a flat tire. frequency of 185 Hz.
A) What frequency do you hear?
B) Suppose after fixing the flat you were driving your car at 22 m/s the truck drives blows his horn again. What frequency do you hear? (Speed of sound in air is 340 mis).
Answer:
(a) the observed frequency is 200 Hz
(b) the observed frequency is 188 Hz.
Explanation:
speed of the truck, Vs = 27 m/s
frequency of the truck as it approaches, Fs = 185 Hz
(a) Apply Doppler effect to determine the frequency you will hear.
As the truck approaches you, the observed frequency will be higher than the source frequency because of decrease in distance.
[tex]F_s = F_o [\frac{V}{V_S + V} ][/tex]
Where;
Fo is the observed frequency which is the frequency you will hear.
V is speed of sound in air
[tex]F_s = F_o [\frac{V}{V_S + V} ]\\\\185 = F_o [\frac{340}{27 + 340} ]\\\\185 = F_o (0.926)\\\\F_o = \frac{185}{0.926}\\\\F_o = 199.78 \ Hz[/tex]
[tex]F_o = 200 \ Hz[/tex]
(b) Apply the following formula for a moving observer and a moving source;
[tex]F_o = F_s[\frac{V-V_o}{V} ](\frac{V}{V-V_S} )[/tex]
The observed frequency is negative since you are driving away from the truck and the source frequency is also negative since it is driving towards you.
[tex]F_o = F_s[\frac{V-V_o}{V} ](\frac{V}{V-V_S} )\\\\F_o = 185[\frac{340-22}{340} ](\frac{340}{340-27} )\\\\F_o = 185(0.9353)(1.0863)\\\\F_o = 188 \ Hz[/tex]
a machine
of efficiency of 70% is used to raise
a body of
mass 80 kg through
a vertical distance of 3m in
40 seconds. Calculate the power input. (Take g = 10 m/s²)
Answer:
Power_input = 85.71 [W]
Explanation:
To be able to solve this problem we must first find the work done. Work is defined as the product of force by distance.
[tex]W = F*d[/tex]
where:
W = work [J] (units of Joules)
F = force [N] (units of Newton)
d = distance [m]
We need to bear in mind that the force can be calculated by multiplying the mass by the gravity acceleration.
Now replacing:
[tex]W = (80*10)*3\\W = 2400 [J][/tex]
Power is defined as the work done over a certain time. In this way by means of the following formula, we can calculate the required power.
[tex]P=\frac{W}{t}[/tex]
where:
P = power [W] (units of watts)
W = work [J]
t = time = 40 [s]
[tex]P = 2400/40\\P = 60 [W][/tex]
The calculated power is the required power. Now as we have the efficiency of the machine, we can calculate the power that is introduced, to be able to do that work.
[tex]Effic=0.7\\Effic=P_{required}/P_{introduced}\\P_{introduced}=60/0.7\\P_{introduced}=85.71[W][/tex]
What best describes the speed of light waves in solids, liquids, and gases?
The speed is fastest in solids.
The speed is fastest in liquids.
The speed is fastest in gases.
The speed is the same in all matter.
Answer: It’s fastest in gases. Letter C !
Explanation:
Answer:
its c
Explanation:
1. A 3.8 kg scooter moves with a constant acceleration of 2.5 m/s”. Determine the net
applied force responsible for the acceleration.
Answer:
9.5 NExplanation:
The force acting on an object given it's mass and acceleration can be found by using the formula
force = mass × acceleration
From the question we have
force = 3.8 × 2.5
We have the final answer as
9.5 NHope this helps you
A ball of mass 4kg moving with a velocity of 20m/s collides with another ball of mass 15kg moving with a velocity of 15m/s in the same direction. Calculate the velocity of the 5kg ball if the collision is perfectly inelastic.
Answer:
velocity = 16.05 m/s
Explanation:
inelastic collision formula:
m1u1 + m2u2 = (m1 + m2)v
m1 = 4kg
u1 = 20m/s
m2 = 15kg
u2 = 15m/s
find v ?
m1u1 + m2u2 = (m1 + m2)v
(4×20) + (15×15) = (4+15)v
80 + 225 = 19v
305 = 19v
19v = 305
v = 305/19
v = 16.05 m/s
ASAP
What is elastic potential energy?
Answer:
Elastic potential energy is stored when materials stretch or compress. Examples of it include springs, rubber bands, and slingshots.
Explanation:
what would the net force be on the box in the problems shown below.( both force and direction). for all four diagrams. please explain answers.
A has a frequency of 300 Hz and a wavelength of 1.10 m. What is the velocity of the wave?
Hello!!
For calculate the Velocity of the wave let's applicate the formula:
[tex]\boxed{V=f*\lambda}[/tex]
[tex]\textbf{Being:}[/tex]
[tex]\sqrt{}[/tex] V = Velocity = ?
[tex]\sqrt{}[/tex] f = Frequency = 300 Hz
[tex]\sqrt{}[/tex] [tex]\lambda[/tex] = Wavelength = 1,1 m
⇒ [tex]\text{Then let's \textbf{replace it according} we information:}[/tex]
[tex]V = 300 \ Hz * 1,1 \ m[/tex]
⇒ [tex]\text{Let's resolve it: }[/tex]
[tex]V = 330 \ m / s[/tex]
[tex]\textbf{Result:}\\\text{The velocity is \textbf{330 meters per second}}[/tex]
Answer:
For calculate the Velocity of the wave let's applicate the formula:
V = Velocity = ?
f = Frequency = 300 Hz
= Wavelength = 1,1 m
⇒
⇒
Explanation:
What is the lithosphere?
A. the outer layer of the Earth's crust
B. the inner core
C. the middle portion of the mantle
D. the outer core
Answer:
a. outer layer
Explanation:
lithosphere is right underneath the continental and ocean crust. it is approximately 100 km in deep and it is a brittle layer. It is broken into tectonic plates.
the inner core is located at the very center and its full of iron and nickel (so its not B)
on top of that is the outer core which is liquid (not D)
the middle portion of the mantle is the asthenosphere and mesosphere. they are right beneath the lithosphere. (not C)
so the best answer is A
As a woman walks, her entire weight is momentarily placed on one heel of her high-heeled shoes. Calculate the pressure exerted on the floor by the heel if it has an area of 1.60 cm2 and the woman's mass is 54.0 kg. Express the force in N/m2 and lb/in2. (In the early days of commercial flight, women were not allowed to wear high-heeled shoes because aircraft floors were too thin to resist such large pressures.)
Answer:
P = 3.3075 x 10⁶ N/m² = 479.71 lb/in²
Explanation:
In order to find the pressure , we first need to find the force exerted by the lady. The force must be equal to the weight of the lady:
Force = F = Weight = mg
F = mg = (54 kg)(9.8 m/s²)
F = 529.2 N
Now, we convert area to S.I unit:
Area = A = (1.6 cm²)(1 m/100 cm)²
A = 1.6 x 10⁻⁴ m²
Now, the pressure can be calculated as:
Pressure = P = F/A
P = 529.2 N/1.6 x 10⁻⁴ m²
P = 3.3075 x 10⁶ N/m²
Now, we convert this into lb/in²:
P = (3.3075 x 10⁶ N/m²)[(0.000145038 lb/in²)/(1 N/m²)
P = 479.71 lb/in²
10. A 90 kg box is sliding across a surface at a constant velocity while experiencing a rightward applied
force of 40 N. Calculate the force of friction acting on the box.
A. -40N
B. +40N
C.-2.5 N
D. 0 N
If the box is moving at constant velocity, net force must be zero, so:
F + fr = 0
fr = -F
fr = -40 N
Help please I would appreciate it
Answer:
i think the red runner travels greater distance ie.40 m
Explanation:
although ,the blue one travels 21 m but in the backward direction .so the correct ans is "the red runner travels 40 m"
how do you determine half life
Answer:
T= In(2)/___ =__ In(2)
Explanation:
the equation pices arnt on the keyboard so i put the blanks
sorry
jope it helps some. Have a good day ir night! :)
the maximum intensity levels of a trumpet, trombone, and a bass drum, each at a distance of 3m are 94 dB, 107dB, and 113dB respectively. What is the intensity level of the three different instruments when played simultaneously, again at 3m?
Answer:
β = 114 db
Explanation:
The intensity of sound in decibles is
β = 10 log [tex]\frac{I}{I_{o}}[/tex]
in most cases Io is the hearing threshold 1 10-12 W / cm²
let's calculate the intensity of each instrument
I / I₀ = 10 (β / 10)
I = I₀ 10 (β / 10)
trumpet
I1 = 1 10⁻¹² 10 (94/10)
I1 = 2.51 10⁻³ / cm²
Thrombus
I2 = 1 10⁻¹² 10 (107/10)
I2 = 5.01 10-2 W / cm²
low
I3 =1 1-12 (113/10) W/cm²
I3 = 1,995 10-1 W / cm²
when we place the three instruments together their sounds reinforce
I_total = I₁ + I₂ + I₃
I_ttoal = 2.51 10-3 + 5.01 10-2 + 1.995 10-1
I_total = 0.00251 + 0.0501 + 0.1995
I_total = 0.25211 W / cm²
let's bring this amount to the SI system
β = 10 log (0.25211 / 1 10⁻¹²)
β = 114 db
An axe used to split wood is driven into a piece of wood for an input distance of 0.05m. If the mechanical
advantage of the axe is 0.85, how far apart (output distance) is the wood split?
The index of refraction of quartz is anisotropic. Suppose that visible light is passing from one grain to another of different crystallographic orientation and at normal incidence to the grain boundary. Calculate the reflectivity at the boundary if the indices of refraction for the two grains are 1.545 and 1.555 in the direction of light propagation. Enter your answer in accordance to the question statement
Answer:
1.04*10⁻⁵
Explanation:
light wave do showcase some behaviors whenever there is encounters with the end of the medium, some of the behaviors are - reflection, refraction, as well as diffraction. When visible light wave strikes a boundary that exist two different media, a portion of the energy will be transmitted into the new medium and some reflected.
Reflection of a light wave can be regarded as bouncing off of light wave from boundary. refraction on other hand is bending of the path of a light wave.
We were to calculate the reflectivity at the boundary,
reflectivity at the boundary can be calculated using the expression below
Reflectivity= (n₂ - n₁)² /(n₂ + n₁ ) ²
where
n₁= Indices of refraction at first grain= 1.545
n₂= Indices of refraction at second grain=
1.555
(1.555 - 1.545)² / (1.555 - 1.545)²
=(0.01)²/ (3.1)²
= 0.0001/ 9.61
= 1.04*10⁻⁵
Hence, the reflectivity at the boundary if the indices of refraction for the two grains are 1.545 and 1.555 in the direction of light propagation is 1.04*10⁻⁵
Which would best help a student determine the net force acting on a rollercoaster car as it moves from one point on its track to another?
Answer:
you can show them a vid
Explanation:
what type of friction present when you wrench on a car?
Answer:Rolling friction is friction that acts on objects when they are rolling over a surface. Rolling friction is much weaker than sliding friction or static friction. This explains why most forms of ground transportation use wheels, including bicycles, cars, 4-wheelers, roller skates, scooters, and skateboards.
Explanation:
The technology in the picture produces which energy conversion?
A. Chemical energy to kinetic energy
B. Thermal energy to kinetic energy
C. Light energy to electrical energy
D. Kinetic energy to electrical energy
Answer:
D
Explanation:
because the whole town needs to be powered through some sort of energy and kinetic energy means the movement of something
The technology in the picture represents the conversion of kinetic energy to electrical energy. So, the correct option is D.
What is meant by kinetic energy ?Kinetic energy of a body is defined as the energy acquired by the body due to the virtue of its motion.
Here,
The given picture represents the dam system at a town.
We know, according to conservation of energy, energy can neither be created nor be destroyed, but can be transferred from one form to another.
In the dam system, the application of conservation of energy is implemented.
Dam consists of a water stream and turbines. The water stream is arranged in such a way that, when the water is running from a height, the water acquires an energy in the form of kinetic energy.
This kinetic energy of the water is converted to electrical energy with the help of the turbines, which are rotating continuously and thus electricity is produced.
Hence,
The technology in the picture represents the conversion of kinetic energy to electrical energy.
To learn more about kinetic energy, click:
https://brainly.com/question/999862
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A pail in a water well is hoisted by means of a frictionless winch, which consists of a spool and a hand crank. When Jill turns the winch at her fastest water-fetching rate, she can lift the pail the 28.0 m to the top in 11.0 s. Calculate the average power supplied by Jill's muscles during the upward ascent. Assume the pail of water when full has a mass of 7.30 kg.
Answer:
182.28 W
Explanation:
Here ,
m = 7.30 Kg
distance , d= 28.0 m
time , t = 11.0 s
average power supplied = change in potential energy/time
average power supplied = m×g×d/time
average power supplied = 7.30×9.81×28/11
average power supplied = 182.28 W
the average power supplied is 182.28 W
A stunt person jumps from the roof of a tall building, but no injury occurs because the person lands on a large, air-filled bag. Which one of the following best describes why no injury occurs?
A. The bag increases the amount of time during which the momentum is changing and reduces the average force on the person.
B. The bag increases the amount of time the force acts on the person and reduces the change in momentum.
C. The bag reduces the impulse to the person.
D. The bag provides the necessary force to stop the person.
E. The bag decreases the amount of time during which the momentum is changing and reduces the average force on the person.
Answer:
A stunt person jumps from the roof of a tall building, but no injury occurs because the person lands on a large, air-filled bag. Which one of the following best describes why no injury occurs?
The bag increases the amount of time during which the momentum is changing and reduces the average force on the person.
ANSWER: A
Answer:
A. The bag increases the amount of time during which the momentum is changing and reduces the average force on the person.
During stunts, people usually put an-air filled bag on the ground for safe landing and to prevent injuries.
Momentum is calculated by m* v where m is for mass and v is for velocity.
Force is directly proportional to momentum
F∝M
The bag in this scenario helps to increases the amount of time the force acts on the person. This implication means that there is a reduction in the change of momentum. Since Force and momentum have a directly proportional relationship then the Force taken to hit the floor is greatly reduced.
Read more on https://brainly.com/question/20362316
A hammer strikes a nail with a 10N force for .01 seconds. Calculate the impulse of the hammer
Answer:
Impulse = 0.1 Kgm/s
Explanation:
Given the following data;
Force, F = 10N
Time, t = 0.01 seconds
To find impulse
An impulse can be defined as the net force acting an object for a very short period of time.
Mathematically, impulse is given by the formula;
Impulse = force * time
Substituting into the equation, we have;
Impulse = 10 * 0.01
Impulse = 0.1 kgm/s
Therefore, the impulse of the hammer is 0.1 kilogram meter per seconds.
The impulse of the hammer is 0.1 Ns.
To solve the given problem we need to use the formula for calculating impulse.
Impulse: This can be defined as the product of force and time on a body.
The formula of impulse is given below.
I = Ft....................... Equation 1
Where :
I = Impulse of the harmerF = Force on the nailt = timeFrom the question,
Given:
F = 10 Nt = 0.01 sSubstitute these values into equation 1
I = 10(0.01)I = 0.1 NsHence, The impulse of the hammer is 0.1 Ns.
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calculate the force necessary to keep a mass of 2 kg moving on a circular path of radius 0.2 m with a period of 0.5 second. what is the direction of this force
You have to move your 100 N couch before a delivery company drops off your new one. Unfortunately your roommate is passed out on it. The coefficient of friction between the couch and floor is .43. It takes 250 N of force to get the couch moving. a) How much does your roommate weigh in Newton’s? b) After you get the couch moving it only takes 200 N to keep it moving at a constant speed, what is the coefficient of kinetic friction?
Answer:
a) Weight of Roommate = 481.4 N
b) μk = 0.34
Explanation:
a)
The force required to move the couch must be equal to the force of friction:
F = frictional force
F = μW
W = F/μ
where,
W = Total Weight of Couch and Roommate
F = Force Required start to move couch = 250 N
μ = coefficient of static friction between couch and floor = 0.43
Therefore,
[tex]W = \frac{250 N}{0.43}\\\\W = 581.4 N[/tex]
So, the total weight is given as:
W = Weight of Couch + Weight of Roommate
Weight of Roommate = W - Weight of Couch
Weight of Roommate = 581.4 N - 100 N
Weight of Roommate = 481.4 N
b)
Now, the force required to keep the couch moving can be given as equal to the kinetic friction force:
F = kinetic friction
F = μk*W
μk = F/W
where,
μk = coefficient of kinetic friction = ?
F = Force required to keep the couch moving = 200 N
Therefore,
μk = 200 N/581.4 N
μk = 0.34
What is net force?
A. The sum of all the forces acting on an object
B. The difference between the largest and smallest forces acting on
an object
C. The largest force acting on an object
D. The smallest force acting on an object
Answer:
A. The sum of all the forces acting on an object.
As a block of mass 42 kilograms drops from the edge of a 40-meter-high cliff it experiences a loss of energy due to air resistance of 81 J. At what speed will the rock hit the ground?
Answer:
The block hits the ground at 27.9 m/s
Explanation:
Gravitational Potential Energy (GPE)
It's the energy stored in an object because of its height in a gravitational field.
It can be calculated with the equation:
U=m.g.h
Where m is the mass of the object, h is the height with respect to a fixed reference, and g is the acceleration of gravity or [tex]9.8 m/s^2[/tex].
When the block is at the edge of the cliff it has potential energy that can be transformed into any other type of energy as it starts falling to the ground.
The GPE of the block of mass m=42 Kg at h=40 m is:
U = 42*9.8*40
U = 16,464 J
The block loses 81 J due to air resistance, thus the energy stored when it hits the ground is 16,464 J - 81 J = 16,383 J.
This energy is stored as kinetic energy, whose formula is:
[tex]\displaystyle K=\frac{1}{2}mv^2[/tex]
Solving for v:
[tex]\displaystyle v=\sqrt{\frac{2K}{m}}[/tex]
[tex]\displaystyle v=\sqrt{\frac{2*16,383 }{42}}[/tex]
[tex]v=\sqrt{780.143}[/tex]
v = 27.9 m/s
The block hits the ground at 27.9 m/s
What energy transformation takes place in the
solar panel?