a 4 kg block is moving at 12 m/s on a horizontal frictionless surface. a constant force is applied such that the block slows with an acceleration of 3 m/s^2. how much work must this force do to stop the block?

Answer 1

F = ma
work = force * distance
(think of the sliding block as compressing a spring, where work = 1/2 kx^2)