Which is not one of Newton's laws of motion?
a) A object in equilibrium will remain so unless acted upon by an outside force.
b) The surm of external forces on a body equals mass times acceleration ( F-ma)
c) For every action, there is an equal and opposite reaction
d) The normal force on a body equals mass times gravity (N mg)
e) All of the above are among Netwon's laws of motion.