4.23 Newton’s Second Law
4.23 Newton’s Second Law
- State Newton’s second law of motion.
- Compare and contrast the effects of force and mass on acceleration.
These boys are racing around the track at Newton’s Skate Park. The boy who can increase his speed the most will
win the race. Tony, who is closest to the camera in this picture, is bigger and stronger than the other two boys, so he
can apply greater force to his skates.
Q: Does this mean that Tony will win the race?
A: Not necessarily, because force isn’t the only factor that affects acceleration.
Force, Mass, and Acceleration
Whenever an object speeds up, slows down, or changes direction, it accelerates. Acceleration occurs whenever an
unbalanced force acts on an object. Two factors affect the acceleration of an object: the net force acting on the object
and the object’s mass.Newton’s second law of motiondescribes how force and mass affect acceleration. The law
states that the acceleration of an object equals the net force acting on the object divided by the object’s mass. This
can be represented by the equation:
Acceleration=Net forceMass
or a=mF
Q: While Tony races along on his rollerblades, what net force is acting on the skates?