Hockey ball of mass 200 gram travelling at 10 metre per second is struck by hockey stick. So as to return it along its original path with a velocity at 5 metre per second calculate the magnitude of change of momentum occurred in the motion of the hockey Ball by the force applied by the hockey stick.

Two students, each riding bicycles, start from the same apartment building and ride to the same building on campus, but each takes a different route. the first student rides 1100 m due east and then turns due north and travels another 1430 m before arriving at the destination. the second student heads due north for 1930 m and then turns and heads directly toward the destination. at the turning point, how far is the second student from the destination?