Forces can be added together only if they are
A. acting on the same object.
B. balanced forces.
C. unaffected by gravity.
D. substantial.


According to Newton’s third law of motion, when a hammer strikes and exerts force on a nail, the nail
A. creates a friction with the hammer.
B. disappears into the wood.
C. exerts an equal and opposite force on the hammer.
D. moves at a constant speed.



Answer each one