The 500 kg car travelling at 25 m s-1 collides head-on with another of mass 800 kg travelling at 18 m s-1 in the opposite direction and they move together after impact. What is the magnitude of their velocity just after impact and in what direction do they move off?

Does work output exceed work input when a machine is used? a) yes, it does, as machines create energy. b) it depends on the type of machine used. c) no, it doesn’t, as machines are inefficient. d) no, it doesn’t, as machines cannot create energy.

Arunner is training for an upcoming marathon by running around a 100-m-diameter circular track at constant speed. let a coordinate system have its origin at the center of the circle with the x-axis pointing east and the y-axis north. the runner starts at (x, y) = (50 m, 0 m) and runs 2.5 times around the track in a clockwise direction.

Which of the following are appropriate acceleration units?