a 2 kg block is placed at the top of an incline and released from rest near earth’s surface and unknown distance h above the ground. the angle θ between the ground and the incline is also unknown. frictional forces between the block and the incline are considered to be negligible. the block eventually slides to the bottom of the incline after 0.75 s. the block’s velocity v as a function of time t is shown in the graph starting from the instant it is released. how could a student use the graph to determine the total energy of the block-earth system?