You push a heavy crate. at first it doesn't move. you push harder, and it finally starts to move, but you still have to exert some force to keep it moving at a constant velocity. explain.

Aplayground merry-go-round has a radius of 4.6 m and a moment of inertia of 200 kg-m2 and turns with negligible friction about a vertical axle through its center. a child applies a 26.0 n force tangentially to the edge of the merry-go-round for 15.0 seconds. if the merry-go-round is initially at rest, how much work did the child do on the merry-go-round?

Metals are good conductors of electricity because they

Energy conservation is the process by which one kind of energy changes into a another and when energy is converted this way it's not lost or used up. true or false