Aroller coaster car is elevated to a height of 30 m and released from rest to roll along a track. at a certain time t it is at a height of 2 m and has lost 25.000 j of energy to friction. the car has a mass of 800 kg. answer the following questions. (a) how fast is the car going at time t? (b) how fast would the car be going at time t if the track were frictionless?

Two manned satellites approaching one another at a relative speed of 0.550 m/s intend to dock. the first has a mass of 2.50 ✕ 103 kg, and the second a mass of 7.50 ✕ 103 kg. assume that the positive direction is directed from the second satellite towards the first satellite. (a) calculate the final velocity after docking, in the frame of reference in which the first satellite was originally at rest.(b) what is the loss of kinetic energy in this inelastic collision? (c) repeat both parts, in the frame of reference in which the second satellite was originally at rest. final velocity(d) loss of kinetic energy = ?