A 20-kg block is originally at rest on a horizontal surface for which the coefficient of s...

A 20-kg block is originally at rest on a horizontal surface for which the coefficient of static friction is μs = 0.6 and the coefficient of kinetic friction is μk = 0.5. If a horizontal force F is applied such that it varies with time as shown, determine the speed of the block in 10 s. Hint: First determine the time needed to overcome friction and start the block moving.