A custodian pulls a vacuum 13.5 m with a 33.9 N force at a 55.0°
angle, against a 14.1 N friction
force. Find the work done by the
custodian.
(Unit = J)

Under the action of a constant force an object accelerates at 7.8 m/s2. what will the acceleration be if (a) the force is halved? (b) the object's mass is halved? (c) the force and the object's mass are both halved? (d) the force is halved and the object's mass is doubled?