You are going 30 m/s in a car of mass 1000 kg when you reach a red light and stop your car. a. How much heat energy is released by the brakes of your car?
b. If your car could recapture 40% of the heat energy released from your brakes, how much energywould you recapture?
c. Imagine that you have an electric car and all of the recaptured energy is put back into the battery that powers your car. What speed could your car achieve from rest by using only the recaptured energy from part (b)

Two friends are having a conversation. anna says a satellite in orbit is in freefall because the satellite keeps falling toward earth. tom says a satellite in orbit is not in freefall because the acceleration due to gravity is not 9.80 m/2 . who do you agree with and why?

Ablock of mass m = 2.5 kg is attached to a spring with spring constant k = 710 n/m. it is initially at rest on an inclined plane that is at an angle of θ = 23° with respect to the horizontal, and the coefficient of kinetic friction between the block and the plane is μk = 0.19. in the initial position, where the spring is compressed by a distance of d = 0.16 m, the mass is at its lowest position and the spring is compressed the maximum amount. take the initial gravitational energy of the block as zero. a) what is the block's initial mechanical energy? b) if the spring pushes the block up the incline, what distance, l, in meters will the block travel before coming to rest? the spring remains attached to both the block and the fixed wall throughout its motion.

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