Newton was first to use the term inertia to describe the tendency of objects to remain in motion or stay at rest. Newton's Second Law describes motion produced by unbalanced forces. The units of force are Newtons . 2 Newton's Third Law explains why forces act in pairs. For every action, there is an equal and opposite reaction.
Forces always act in pairs .
Scoring criteria List the forces acting on you while sitting in a chair. Give the reasoning for your answer. Tell which of Newton's Laws applies to each of these situations. The space shuttle leaving the launch pad. A small car gets better gas milage than a big car.