A crate of mass 50 kg is being pushed across a rough surface at a steady 8.0 m/s. The crate is then released and comes to a stop in 10 seconds. What is the average rate at which the frictional force on the crate removes kinetic energy from it?
A boy pulls a 5.00-kg cart with a 20.0-N force at an angle of above the horizontal for a length of time. Over this time, the cart moves a distance of 12.0 m on the horizontal floor.
Find the work done on the cart by the boy.
What will be the work done by the boy if he pulled with the same force horizontally instead of at an angle of above the horizontal over the same distance?