The motor M pulls on the cable with a force of F, which has a magnitude that varies as s...

The motor M pulls on the cable with a force of F, which has a magnitude that varies as shown on the graph. If the 20-kg crate is originally resting on the floor such that the cable tension is zero at the instant the mot& is turned on, determine the speed of the crate when t = 6 s. Hint: First determine the time needed to begin lifting the crate.