(adsbygoogle = window.adsbygoogle || []).push({}); 1. Assume that a car who has a mass of 1000kg (including driver) is initially rolling freely (without using the engine) down a 30° slope at a speed of 5m/s. The brakes are used causing the car to stop after 10 m.

Find the HEAT CAPACITY of the brakes if they rise in temperature by 10 K.

Drag forces are negligible, no heat transfer to or from the car occurs and the only change in U (internal energy) is due to heating of the brakes

2. I need to find Q

Q = mc(Tf-Ti)

Using conservation of energy

W + Q = ΔK.E + ΔP.E + ΔU

W = sin(30) * d

K.E = (1/2)mv^{2 }

The rest I do not know?!

3. The answer is C =6.25 x 10^{3 }but I do not know how this is obtained.

What confuses me is the part that says that ΔU is not zero and that there is no heat transfer to or from the car.

What is the correct method in order to obtain that answer?

Thank you

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# Homework Help: What is the heat capacity of the tires of the car?

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