1) A 6.0kg box slides a 11m distance on ice. If the coefficient of kinetic friction is 0.30, what is the work done by the friction force?
2) A 800kg , light-weight helicopter ascends from the ground with an acceleration of 3.50m/s2 . Over a 4.00s interval, what is the work done by the lifting force? What is the work done by the gravitational force? What is the work done by the net force on the helicopter?