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Bernard says that a mass executing uniform circular motion is not accelerating as it's speed is not changing. Which parts of his statement are correct and which are false. For those which are false state why they are and give the correct version.
Correct:For a mass which is executing uniform circular motion, it's speed doesn't change.
False:(1) A mass which is executing uniform circular motion is not accelerating
Correction to (1)
A car of mass 1000 kg is travelling at 15 m/s. The driver applies the brakes for 4 seconds, slowing the car to 5 m/s. What is the average power output of the brakes over the 4 seconds? Assume there are no other forces acting on the car.
Kinetic Energy, EK=(1/2)mv2. Energy is conserved, so the work done by the brakes, W, must be equal to the change in kinetic energy of the car, ∆EK. Therefore: W = ∆EK = (1/2)1000(15
