Answer:
Conductivity, [tex]\sigma=500\ (\Omega-m)^{-1}[/tex]
Explanation:
Given that,
The resistivity of a material, [tex]\rho=2\times 10^{-3}\ \Omega-m[/tex]
We need to find the conductivity of the material.
We know that the reciprocal of resistivity is called conductivity.
[tex]\sigma=\dfrac{1}{\rho}\\\\\sigma=\dfrac{1}{2\times 10^{-3}}\\\\\sigma=500\ (\Omega-m)^{-1}[/tex]
So, the conductivity of the material is [tex]500\ (\Omega-m)^{-1}[/tex].
A boy throws a rock with an initial horizontal velocity of 17.0 m/s and an initial vertical velocity of 21.0 m/s. How high above the boy's hand is the rock after 2.8 s?
Answer:
53.2
Explanation:
You can use the kinematic equation: displacement of x = (initial velocity + final velocity)*t/2
Subsititing: 17+21 = 38 * 2.8/2 = 53.2
Note: Displacement = distance between the 2 points
A 0.1 kg arrow with an initial velocity of 30 m/s hits a 4.0 kg melon initially at rest on a friction-less surface. The arrow emerges out the other side of the melon with a speed of 20 m/s. What is the speed of the melon? Why would we normally not expect to see the melon move with the is speed after being hit by the arrow?
Answer:
Speed of the melon = 0.25 m/s
we would normally don't see the melon moving due to friction with the resting surface.
Explanation:
We use conservation of momentum:
Pi = Pf
with Pi = 0.1 kg * 30 m/s = 3 kg m/s
and Pf = 0.1 kg * 20 m/s + 4.0 kg * V = 2 kg m/s + 4 * V
Then using the equality above, we solve for V (velocity of the melon)
3 kg m/s = 2 kg m/s + 4 V
1 kg m/s = 4 kg * V
Then V = 1 / 4 M/s = 0.25 m/s
So we would normally don't see the melon moving due to friction with the resting surface.
A ship sets out to sail to a point 141 km due north. An unexpected storm blows the ship to a point 102 km due east of its starting point. (a) How far and (b) in what direction (as an angle from due east, where north of east is a positive angle) must it now sail to reach its original destination
Answer:
Explanation:
The point of destination is 141 north and 102 km east . Vectorially it is represented by unit vector as follows .
D = 102 i + 141 j
magnitude of D = √ ( 102² + 141² )
= √ ( 10404 + 19881)
= √ 30285
= 174 km
To go back to original position , ship should move on the following vector
D = -102 i - 141 j
Tan Ф = 141 / 102 = 1.38
Ф = 54⁰ , direction will be south of west . From north east , angle will be
180 + 54 = 234⁰
acceleration greater than 1,000 m/s2 lasting for at least 1 ms will cause injury. Suppose a small child rolls off a bed that is 0.63 m above the floor. If the floor is hardwood, the child's head is brought to rest in approximately 1.8 mm. If the floor is carpeted, this stopping distance is increased to about 1.3 cm. Calculate the magnitude and duration of the deceleration in both cases, to determine the risk of injury. Assume the child remains horizontal during the fall to the floor. Note that a more complicated fall could result in a head velocity greater or less than the speed you calculate. hardwood floor magnitude m/s2 hardwood floor duration ms carpeted floor magnitude m/s2 carpeted floor duration ms g
A particle with a charge of -4.3 μC and a mass of 4.4 x 10-6 kg is released from rest at point A and accelerates toward point B, arriving there with a speed of 80 m/s. The only force acting on the particle is the electric force. What is the potential difference VB - VA between A and B? If VB is greater than VA, then give the answer as a positive number. If VB is less than VA, then give the answer as a negative number.
Answer:
ΔV = - 3274 V
Explanation:
For this exercise we can use conservation of energy
starting point.
Em₀ = U = q ΔV
final point
Em_f = K = ½ m v²
energy is conserved
Em₀ = Em_f
q ΔV = ½ m v²
ΔV = [tex]\frac{m \ v^2 }{q}[/tex]
let's calculate
ΔV = [tex]\frac{4.4 \ 10^{-6} \ 80^2 }{ 2 \ 4.3 10^{-6} }[/tex]
ΔV = 3274.4 1 V
since the charge q is negative, the potential at point B must be less than the potential at point A, so the answers
ΔV = - 3274 V
A young gazelle is grazing in a beautifully sunlit corner of the savanna. Suddenly, the gazelle raises herhead and spots a lioness in the tall grass 173 m away, so she turns away running at roughly constantspeed. The lioness immediately chases the gazelle, with an explosive acceleration of 2.57 m/s2. Aninformed source tells us that this lioness is capable of enduring her maximum speed of 21.0 m/s for 25.0seconds at the longest. [Assume that both predator and prey never change their direction or motion inthis case, for the sake of simplicity.]
(a) On average, how fast (at least) does that gazelle need to run to survive? [Show all your steps.]
(b) Produce a qualitative graph of animal's position (vertical axis) versus time (horizontal axis), shared for the lioness's motion and as well as the gazelle's. Place graph labels in a way that fits the narration.
Answer:
a) v₂ = 13.20 m / s
Explanation:
To solve this exercise we will use the kinematic relations
Let's start with the Lioness. Let's find the time to reach top speed
v = v₀ + a t
as part of rest, its initial velocity is zero
t = v / a
t₁ = 21.0 / 2.57
t₁ = 8.17 s
the total time is the acceleration time plus the time (t₂ = 25 s) that the maximum speed can withstand
t = t₁ + t₂
t = 8.17 +25.0 = 33.17 s
Now let's find out what distance the lioness travels in these times
during acceleration
x = v₀ t + ½ a t²
x = ½ a t²
x₁ = ½ 2.57 8.17²
x₁ = 85.77 m
during constant speed part
x₂ = v t₂
x₂ = 21.0 25.0
x₂ = 525 m
therefore the total distance traveled is
x = x₁ + x₂
x = 85.77 + 525
x = 610.77 m
a) the average speed of the gazelle
this must be the distance that the lioness travels minus the initial distance that separates the two animals (xo = 173 m) between the time taken
v₂ = [tex]\frac{x -x_o}{t}[/tex]
v₂ = [tex]\frac{610.77 - 173}{33.17}[/tex]
v₂ = 13.20 m / s
b) in the attachment we can see a graph of the displacement of the two animals
What is a watt a unit of?
light
time
distance
power
Answer:
power...............m....
Answer:
The dimension of power is energy divided by time. In the International System of Units (SI), the unit of power is the watt (W), which is equal to one joule per second.
SI unit: watt (W)
In SI base units: kg⋅m2⋅s−3
Explanation:
During a phase change the temperature of a substance remains constant this is because during a phase heat changes the ____ energy of particles in a substance without changing their ____ energy
Answer:
Explanation:
individual and then net
hope that helps I could be wrong about this one though
A pendulum is placed on a distant planet. The length is one meter, and the measured period is 1.4 seconds, what is the acceleration of gravity on that planet?
Answer:
[tex]a=20.14\ m/s^2[/tex]
Explanation:
The time period of the simple pendulum is given by :
[tex]T=2\pi \sqrt{\dfrac{l}{g}}[/tex]
l is the length of the pendulum
g is the acceleration due to gravity
We have,
T = 1.4 s, l = 1 m
So,
[tex]T^2=\dfrac{4\pi^2 l}{g}\\\\g= \dfrac{4\pi^2 l}{T^2}\\\\g= \dfrac{4\pi^2 \times 1}{(1.4)^2}\\\\g=20.14\ m/s^2[/tex]
So, the acceleration due to gravity of that planet is [tex]20.14\ m/s^2[/tex].
How does the length of the pendulum affect the amount of potential energy it starts with? (A longer string will have a greater change in height for the same angle)
Answer:
This is somewhat of a confusing question.
Zero potential energy is usually used to refers to the zero potential energy of objects at infinity. Thus, bringing an object from infinity requires negative work because work is done by the object. One could also choose the pivot point of the pendulum as zero potential. Then any objects above the pivot point would be at a positive potential, and objects below the pivot point would have a negative potential (the object does work moving to a point of lower potential).
Basically, work done "on" an object requires positive potential energy input while work done "by" the object requires negative energy input.
Those are the basic considerations in solving potential energy problems.
A block is pushed so that it moves up a ramp at constant speed. Identify from choices (a)-(e) below the appropriate description for the work done by the specified force while the block moves from point A to point B. (a) is zero. (b) is less than zero. (c) is greater than zero. (d) could be positive or negative depending on the choice of coordinate systems. (e) cannot be determined.
Answer:
*The work of the Normal (N) y Wy are zero answer a
*The work of the applied force (F1) is positive answer c
*The work of the friction force (fr) is negative, answer b
*The work of the Wy isnegative, answer d
Explanation:
In this exercise it is asked to identify the type of work, unfortunately the diagram cannot be seen, but in the attached we can see the diagram of a body moving upward on an inclined plane, the existing forces are shown.
As the body moves at constant speed the accelerations are zero. Let's look for the job that is defined
W = F. d
W = F d cos θ
where the dot represents the dot product and the bold letters are vectors.
* The work of the Normal (N) and the y component of the weight (Wy) are zero because they are perpendicular to the motion
answer a
* The work of the applied force (F1) is positive because it is in the same direction of motion
W = F1 Δx
answer c
* The work of the friction force (fr) is negative because the force in the displacement have opposite directions
W = -fr Δx
answer b
* the work the x component of the weight (Wx) in this case is negative
answer d
a ball has a mass of 140g if it thrown with a velocity of 450m/s what is its kenetic energy?
Kinetic energy = mv²
Therfore kinetic energy =14175 joule
What is the frequency of highly energetic ul-
traviolet radiation that has a wavelength of
124 nm?
The speed of light is 3 x 108 m/s.
Answer in units of Hz.
Frequency = (speed) / (wavelength)
Frequency = (3 x 10⁸ m/s) / (124 x 10⁻⁹ m)
Frequency = 2.42 x 10¹⁵ Hz
pls help ;-; this is the question btw
The answer is "Infrared"
Hope this helps
Answer:
x-rays
Explanation:
A 20-turn coil of area 0.32 m2 is placed in a uniform magnetic field of 0.055 T so that the perpendicular to the plane of the coil makes an angle of 30∘ with respect to the magnetic field.
The flux through the coil is
Answer:
1.5 * 10^-2 Tm^2
Explanation:
Electric Flux = B.A cos(theta)
B = 0.055 T
A = 0.32 m^2
theta = 30
Electric Flux = (0.055 T).(0.32 m^2).Cos(30) = 0.0152 = 1.5 * 10^-2 Tm^2
In the Dorben Company and industrial engineer designed a workstation where the seeing task was difficult because of the size of the components going into the assembly. The desired brightness was 100 fL and the workstation was painted a medium green with a reflectance of 50 percent. What illumination in foot-candles would be required at this workstation to provide the desired brightness? Estimated the required illumination if you repainted the workstation with a light cream paint. what is the luminance of a surface having a 50 % reflectance and a 4 fc illumination?
Answer:
Illumination = 200 fc
luminance = 2FL
Explanation:
given data
desired brightness = 100 fL
painted medium green reflectance = 50 percent
illumination = 4c
solution
we get here Illumination by using the formula that is
Illumination = luminance ÷ reflectance ......................1
Illumination = 100 fL ÷ 0.50
Illumination = 200 fc
With light colored cream paint with a reflectance of 75% the required illumination is 133 fc.
and
luminance will be
luminance = Illumination × reflectance = 4fc × 0.5 = 2FL
A student swings a 0.5kg rubber ball attached to a string over her head in a horizontal, circular
path. The string is 1.5 meters long and in 60 seconds the ball makes 120 complete circles.
What is the velocity of the ball?
What is the ball’s centripetal acceleration?
What is the ball's centripetal force?
Answer:
The balls velocity is 1 divided by 3
The velocity of the ball is 18.85 m/s.
The ball’s centripetal acceleration is 236.87 m/s².
The ball's centripetal force is 118.44 Newton.
What is centripetal acceleration?Centripetal acceleration is a characteristic of an object's motion along a circular path. Centripetal acceleration applies to any item travelling in a circle with an acceleration vector pointing in the direction of the circle's center.
Given parameters:
length of the string: l = 1.5 meters.
Time interval = 60 seconds.
Total number of complete rotation = 120.
Hence, the velocity of the ball = 120×2π×1.5/60 m/s
= 18.85 m/s.
The ball’s centripetal acceleration = (velocity)²/ radius
= (18.85)²/1.5 m/s²
= 236.87 m/s²
The ball's centripetal force = mass × centripetal acceleration
= 0.5 × 236.87 Newton
= 118.44 Newton
Learn centripetal acceleration here:
https://brainly.com/question/14465119
#SPJ2
Secondly, a man is rock climbing when suddenly the rock face he grabs breaks away and he is left with a 1200 lb. rock on his chest. How do scientists say he was able to lift this incredible weight and save himself
Answer:
rush of adrenaline
Explanation:
This is believed to have been possible due to the rush of adrenaline that the individual was experiencing. This has happened a couple times in moments of extreme distress where an individual's body is flooded with adrenaline. This adrenaline allows for super human like strength as well as increased senses. The individual that has lifted the most amount of weight in such a scenario, lifted a total of 3000 lbs. Therefore, it is fair to say that 1200 lb. rock was lifted due to adrenaline.
Basketball player Darrell Griffith is on record as
attaining a standing vertical jump of 1.2 m (4 ft).
(This means that he moved upward by 1.2 m after
his feet left the floor.) Griffith weighed 890 N (200
lb). g=9.8 m/s2
1- What is his speed as he leaves the floor?
2- if the time of the part of the jump before his feet left the floor was 0.300s, what was the magnitude of his average acceleration while he was pushing against the floor?
Explanation:
1.
We use the equation
h = [tex]\frac{gt^2}{2}[/tex], where
h is the height traveled,
g is the acceleration due to gravity and
t is the time taken to reach height h.
We can now calculate t to be
[tex]\sqrt{\frac{2*1.2 m}{9.81 m/s^2} }[/tex]
= 0.495 s
Let v be the initial velocity of the player.
The player deaccelarates from v m/s to 0 m/s in 0.495 s at the rate of 9.81 m/s^2.
v = 9.81 m/s^2 x 0.495 s = 4.85 m/s
2.
The player takes 0.3 s to increase his velocity from 0 m/s to 4.85 m/s. So his average accelaration is
4.85 m/s / 0.3 s = 16.2 m/s^2
Which electrons are transferred in an ionic bond?
Answer:
electrons are completely transferred from one atom to another. In the process of either losing or gaining negatively charged electrons, the reacting atoms form ions. The oppositely charged ions are attracted to each other by electrostatic forces, which are the basis of the ionic bond.
Explanation:
ASAP please thank you !
Find O and P
Explanation:
O + 6V = 9V, so O = 3V
P = 9V as it is parallel to the 9V power supply.
Arrange the objects in order from greatst to least of potential energy assume that gravity is constant
Answer:
Water > Box of books > Stone > Ball
Explanation:
We'll begin by calculating the potential energy of each object. This can be obtained as follow:
For stone:
Mass (m) = 15 Kg
Acceleration due to gravity (g) = 10 m/s²
Height (h) = 3 m
Potential energy (PE) =?
PE = mgh
PE = 15 × 10 × 3
PE = 450 J
For water:
Mass (m) = 10 Kg
Acceleration due to gravity (g) = 10 m/s²
Height (h) = 9 m
Potential energy (PE) =?
PE = mgh
PE = 10 × 10 × 9
PE = 900 J
For ball:
Mass (m) = 1 Kg
Acceleration due to gravity (g) = 10 m/s²
Height (h) = 20 m
Potential energy (PE) =?
PE = mgh
PE = 1 × 10 × 20
PE = 200 J
For box of books:
Mass (m) = 25 Kg
Acceleration due to gravity (g) = 10 m/s²
Height (h) = 2 m
Potential energy (PE) =?
PE = mgh
PE = 25 × 10 × 2
PE = 500 J
Summary:
Object >>>>>>>> Potential energy
Stone >>>>>>>>> 450 J
Water >>>>>>>>> 900 J
Ball >>>>>>>>>>> 200 J
Box of books >>> 500 J
Arranging from greatest to least, we have:
Object >>>>>>>> Potential energy
Water >>>>>>>>> 900 J
Box of books >>> 500 J
Stone >>>>>>>>> 450 J
Ball >>>>>>>>>>> 200 J
Water > Box of books > Stone > Ball
From the center of the Earth to the moon, what should the orbital radius of such satellite be in order to stay over the same point on the earth’s surface?
In order to have a period that matches the Earth's rotation, a satellite must be in a circular orbit, and 42,164 km from the center of the Earth.
But that's not quite enough to make sure that it always stays over the same point on the Earth's surface (and appears motionless in the sky). For that to happen, the satellite's orbit has to be directly over the Equator.
The Moon has nothing to do with any of this.
Students perform an experiment in which they drop two eggs with equal mass from a balcony. In the first trial, the egg hits the ground and breaks. In the second trial, the egg hits a foam cushion and does not break or bounce.
Answer: C
Explanation: Because it is just got the same question on the Impulse and Momentum quiz
What is moral duty?Please tell me the answer of this question.
Explanation:
Moral duties are the duties performed by the people on the basis of humanity and moral values. The following are some of the moral duties :
Respecting elders and loving juniorsHelped the needy , poor and helpless peopleHaving friendly behavior with othersRespecting everyone as human beingBeing obedient and respectful to parents , elderly people and teachers.Living ideal and respectful lifeHope I helped ! ♡
Have a wonderful day / night ! ツ ▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁
what do you call these sound waves whose frequency is above 20000 hertz
Answer:
Untrasound
Explanation:
Your welcome :)
What is the momentum of a 100-kilogram fullback carrying a football on a play at a velocity of 3.5 m/sec.
Answer:
100 Kg * 3.5 m/sec = 350 Kg-m/s
Explanation:
Momentum= F= Δ(mv) with m= mass, v= velocity, and Δ the change in mass and velocity
In this problem you are given all the factors you need to solve the equation you simply just plug in your mass (1,000 Kg) and Velocity (3.5m/s) and multiply them by each other to get your answer
___is found in fruits and honey. *
1.Maltose
2.Sucrose
3.Fructose
4.Galactose
Answer:
3. Fructose
Explanation:
Fructose is a sugar found naturally in fruits, fruit juices, some vegetables and honey.
it is number 3 (Fructose)
Police driving with a velocity of 50 m/s decide to chase a speeder who is 3 km ahead and moving at 55 m/s. The police car accelerates at 2 m/s2. Instantly the speeder becomes aware that he is being chased and starts to accelerate at 1 m/s2. How much time (in s) passes until the police catch the speeder
Answer:
The time that passes until the police catch the speeder is 82.6204 seconds.
Explanation:
A body performs a uniformly accelerated rectilinear motion or uniformly varied rectilinear motion when its path is a straight line and its acceleration is constant. This implies that the speed increases or decreases its modulus in a uniform way.
The position is calculated by the expression:
x = x0 + v0*t + 1/2*a*t²
where:
x0 is the initial position. v0 is the initial velocity. a is the acceleration. t is the time interval in which the motion is studied.First, let’s look at the police car’s equations of motion. In this case:
x0= 0 v0= 50 m/s a= 2 m/s²So: x = 50 m/s*t + 1/2*2 m/s²*t²
Now for the speeder’s car’s equations of motion you know:
x0= 3 km= 3,000 m v0= 55 m/s a= 1 m/s²So: x = 3,000 m + 55 m/s*t + 1/2*1 m/s²*t²
When the police catch the speeder they are both in the same position. So:
50 m/s*t + 1/2*2 m/s²*t²= 3,000 m + 55 m/s*t + 1/2*1 m/s²*t²
Solving:
0= 3,000 m + 55 m/s*t + 1/2*1 m/s²*t² - 50 m/s*t - 1/2*2 m/s²*t²
0= 3,000 + 55 *t + 1/2*t² - 50*t - 1*t²
0= 3,000 + 55 *t - 50*t - 1*t² + 1/2*t²
0= 3,000 + 5*t - 1/2*t²
Applying the quadratic formula:
[tex]x1,x2=\frac{-5+-\sqrt{5^{2}-4*(-\frac{1}{2})*3000 } }{2*(-\frac{1}{2} )}[/tex]
x1= -72.6209
and x2= 82.6209
Since you are calculating the value of a time and it cannot be negative, then the time that passes until the police catch the speeder is 82.6204 seconds.
Help please ............
Answer:
Explanation:
Electrical current is the movement of charge. The units are Amperes (Amps)