The 20-lb block is moving to the right with a velocity of 2 ft/sec on a horizontal surfa...

The 20-lb block is moving to the right with a velocity of 2 ft/sec on a horizontal surface when a force P is applied to it at time t = 0. Calculate the velocity v of the block when t = 0.4 sec. The coefficient of kinetic friction is μ = 0.30.