1. Mary exerts an upward force of 40 N to
hold a bag of groceries. Describe the reaction force (Newtons third law) by
stating (a) its magnitude, (b) its direction, (c) on what object it is exerted,
and (d) by what object it is exerted.
2. What force is needed to accelerate a
child on a sled (total mass 55 kg) at 1.4 m/s2?