A worker pushes horizontally on a 25 kg crate resting on ground level. The coefficients of static and kinetic friction are 0.4 and 0.3.?

Question

a) How much force must he apply to start the crate moving?

b) After the crate has stereo moving, how much force must he apply to move the crate with a constant velocity of 2.0 m/s?

c) After the crate has started moving, how much force must've apply to move the crate with a constant acceleration of 2.0 m/s^2?