1. A 2.5 kg basketball is dropped from the top of a building. Its acceleration is found to be 9.4 m/s^2 as it drops to the ground. What is the force of air friction on the balls as it falls?
2. A 30 kg box sits on the floor. It needs 275 n of force to get it moving. Once it is moving it only takes 225N of force. What are the coefficients of static and kinetic friction?