A thief was trying to pull a 20 kg coffer (a coffer is a box usually used to hold valuables) along an essentially frictionless horizontal surface. The tension in the rope was 25 N and the rope made an angle of 30° with respect to the horizontal. The thief pulled the coffer over a distance of 5 m.
What was the work done on the coffer by the rope?
The coffer was pulled from rest. What was the change in the coffer´s kinetic energy by the end of the 5 m trip?
What was the coffer´s speed at the end of the trip?