Investigating Newton's 2nd Law

1. Newton’s Laws of Motion
Overview

2. Background
Sir Isaac Newton (1643-1727) an English
scientist and mathematician famous for his
discovery of the law of gravity also
discovered the three laws of motion.
Today these laws are known as Newton’s
Laws of Motion and describe the motion of
all objects on the scale we experience in our
everyday lives.

3. Definitions:
Newton’s First Law:
Objects in motion tend to stay in motion
and objects at rest tend to stay at rest
unless acted upon by an unbalanced force.
Newton’s Second Law:
Force equals mass times acceleration
(F = ma).
Newton’s Third Law:
For every action there is an equal and
opposite reaction.

4. Newton’s Second Law
Acceleration is produced when a force acts on a
mass. The greater the mass (of the object
being accelerated) the greater the amount of
force needed.
F = ma
Force = MASS times ACCELERATION

5. 22ndnd
LawLaw
The net force of an object isThe net force of an object is
equal to the product of itsequal to the product of its
mass and acceleration, ormass and acceleration, or
F=ma.F=ma.

6. 22ndnd
LawLaw

7. 22ndnd
LawLaw
When mass is in kilograms andWhen mass is in kilograms and
acceleration is in m/s/s, the unit of force isacceleration is in m/s/s, the unit of force is
in newtons (N).in newtons (N).
One newton is equal to the force requiredOne newton is equal to the force required
to accelerate one kilogram of mass at oneto accelerate one kilogram of mass at one
meter/second/second.meter/second/second.

8. Newton’s 2nd
Law proves that different masses accelerate to the
earth at the same rate, but with different forces.
 We know that objects
with different masses
accelerate to the
ground at the same
rate.
 However, because of
the 2nd
Law we know
that they don’t hit the
ground with the same
force.
F = maF = ma
98 N = 10 kg x 9.8 m/s/s98 N = 10 kg x 9.8 m/s/s
F = maF = ma
9.8 N = 1 kg x 9.89.8 N = 1 kg x 9.8
m/s/sm/s/s

9. 5.2 The Second Law:
Force, Mass, and Acceleration
Investigation Key Question:
What is the relationship
between force, mass, and
acceleration?

10. 5.2 The Second Law:
Force, Mass, and Acceleration
Investigation Key Question:
What is the relationship
between force, mass, and
acceleration?