A truck speeding down the highway has a lot of kinetic energy relative to a stopped state trooper but no kinetic energy relative to the truck driver. In these two frames of reference, is the same amount of work required to stop the truck? Explain.

Solution 14DQ Step 1 : In driver’s frame of reference the truck is not moving, hence there is no work needed to stop the truck with respect to driver But in the highway frame of reference the truck is moving with lot of kinetic energy , hence in this frame of reference work has to be done to stop the truck Since the velocity of the truck is relative to the frame of reference the kinetic energy is also relative to the frame of reference We know 2 KE = 1/2 mv Since we have two frame frame of reference Let us consider K 1nd K 2 Such that dK = K 1 2 We can write as dK = 1/2m(v (v/4) ) 2 Hence we can infer that kinetic energy depends on the magnitude of velocity and not the direction