An ice skater glides for two meters across ice is work done or no work done

In a bumper car arena, two cars of equal mass are heading straight toward each other. the orange one is traveling at a speed of 5 meters per second. the green one is traveling at a speed of 2 meters per second. which of the forces most affects the motion of the bumper cars after they collide? a) gravity b) friction c) the other car d) wind resistance

To do work, this truck uses energy stored in chemical fuel and an electrical battery. how much total energy does this truck put out?

Phase changes are chemical changes. true or false