4. A boy pulls a 50 kg crate across a level floor with a force of 200N, as shown. 200 N If the force acts at an angle of 30 to the horizontal and the coefficient of kinetic friction is 0.30, determine: 50 kg - . . a) the normal force and the horizontal frictional force exerted on the crate by My = 0.30 the floor. b) the acceleration of the crate. c) the work done by the 200 N force in moving the crate 5 metres