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3 years ago

What is kinetic friction ? what causes it ? what does it generate ?

Physics

1 answer:

diamong [38]3 years ago

3 0

Answer:

What is kinetic friction?

Kinetic friction is defined as a force that acts between moving surfaces. A body moving on the surface experiences a force in the opposite direction of its movement.

What causes it?

When the mass is not moving, the object experiences static friction. The friction increases as the applied force increases until the block moves. After the block moves, it experiences kinetic friction, which is less than the maximum static friction.

What does it generate?

When surfaces in contact move relative to each other, the friction between the two surfaces converts kinetic energy into thermal energy (that is, it converts work to heat). This property can have dramatic consequences, as illustrated by the use of friction created by rubbing pieces of wood together to start a fire.

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The temperature will (A) Decrease.

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3 years ago

A stunt man jumps from the top of a building and lands 10 meters below his initial height. In case A, the stunt man lands on a s

krek1111 [17]

Answer:

Explanation:

The stunt will likely sustain serious injury in case of concrete blocks because the average force acting on the person will be more because concrete blocks do not squeeze to provide more time for the force to act on the body instead it acts for a small amount of interval.

$Impulse=F_{avg}\times \Delta T$

As impulse is constant so time requires to act force on the body is more as compared to concrete block and thus average force in mattress case is less.

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3 years ago

PLEASE HELP ASAP!!!

musickatia [10]

Answer:

22.2 W

Explanation:

First of all, we calculate the work done by moving the wagon, using the formula:

$W=Fdcos \theta$

where

F = 20 N is the magnitude of the force

d = 1000 m is the displacement of the wagon

$\theta=0^{\circ}$ is the angle between the direction of the force and of the displacement (assuming the force is applied in the direction of motion)

Substituting, we find

$W=(20)(1000)=20,000 J$

Now we can find the power generated, which is equal to the ratio between the work done and the time taken:

$P=\frac{W}{t}$

where

W = 20,000 J

t = 15 min = 900 s

Substituting,

$P=\frac{20000}{900}=22.2 W$

And the same value in Joules/second (remember that 1 Watt = 1 Joule/second)

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3 years ago

What is the answer to 895cm a Km

victus00 [196]

Answer:

if you're converting then the answer is 0.00895

Explanation:

895 centimetres converted into kilometres= 0.00895

8 0

2 years ago

Four long wires are each carrying 6.0 A. The wires are located

Firdavs [7]

Answer:

$B_T=2.0*10^-5[-\hat{i}+\hat{j}]T$

Explanation:

To find the magnitude of the magnetic field, you use the following formula for the calculation of the magnetic field generated by a current in a wire:

$B=\frac{\mu_oI}{2\pi r}$

μo: magnetic permeability of vacuum = 4π*10^-7 T/A

I: current = 6.0 A

r: distance to the wire in which magnetic field is measured

In this case, you have four wires at corners of a square of length 9.0cm = 0.09m

You calculate the magnetic field in one corner. Then, you have to sum the contribution of all magnetic field generated by the other three wires, in the other corners. Furthermore, you have to take into account the direction of such magnetic fields. The direction of the magnetic field is given by the right-hand side rule.

If you assume that the magnetic field is measured in the up-right corner of the square, the wire to the left generates a magnetic field (in the corner in which you measure B) with direction upward (+ j), the wire down (down-right) generates a magnetic field with direction to the left (- i) and the third wire generates a magnetic field with a direction that is 45° over the horizontal in the left direction (you can notice that in the image attached below). The total magnetic field will be:

$B_T=B_1+B_2+B_3\\\\B_{T}=\frac{\mu_o I_1}{2\pi r_1}\hat{j}-\frac{\mu_o I_2}{2\pi r_2}\hat{i}+\frac{\mu_o I_3}{2\pi r_3}[-cos45\hat{i}+sin45\hat{j}]$

I1 = I2 = I3 = 6.0A

r1 = 0.09m

r2 = 0.09m

$r_3=\sqrt{(0.09)^2+(0.09)^2}m=0.127m$

Then you have:

$B_T=\frac{\mu_o I}{2\pi}[(-\frac{1}{r_2}-\frac{cos45}{r_3})\hat{i}+(\frac{1}{r_1}+\frac{sin45}{r_3})\hat{j}}]\\\\B_T=\frac{(4\pi*10^{-7}T/A)(6.0A)}{2\pi}[(-\frac{1}{0.09m}-\frac{cos45}{0.127m})\hat{i}+(\frac{1}{0.09m}+\frac{sin45}{0.127m})]\\\\B_T=\frac{(4\pi*10^{-7}T/A)(6.0A)}{2\pi}[-16.67\hat{i}+16.67\hat{j}]\\\\B_T=2.0*10^-5[-\hat{i}+\hat{j}]T$

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4 years ago