An automobile travels on a straight road for 25 km at 32 km/h. it then continues in the same direction for another 25 km at 64 km/h. (a) what is the average velocity of the car during this 50 km trip? (assume that it moves in the positive x direction.) (b) what is the average speed? g

A14 kg rock starting from rest free falls through a distance of 5.0 m with no air resistance. find the momentum change of the rock caused by its fall and the resulting change in the magnitude of earths velocity. earth mass is 6.0 * 10^24 kg. show your work assuming the rock earth system is closed.