Law of Acceleration
An introduction to the relationship
between force, mass, and
acceleration
Lesson Outline
Newton's Second Law of Motion
Force and Acceleration
Mass and Acceleration
Did You Know?
Mountainous roads have a feature
called "runaway truck ramps" to
allow large trucks and buses to
stop safely.
Why do large vehicles need this
ramp?
How does it relate to the law of
acceleration?
Large vehicles may gain speed due to
the force of gravity.
Gravel is a common material for
runaway truck ramps. It
provides enough friction to
bring a runaway truck to a stop.
Newton's
states
that
the
acceleration
Second Law equals the net force acting on
of Motion
an object divided by mass
Statement
Also known as the
"law of acceleration"
Expression
force
Describes how force
and mass affect
acceleration
F
a=
m
acceleration
OR
mass
F = ma
Force and Acceleration
smaller
acceleration
less
force
larger
acceleration
more
force
At constant mass, acceleration increases as force increases.
Think About It!
Which will move faster after
being pushed—a block of foam
or a heavy brick? Why?
Mass and Acceleration
larger mass
less mass
larger
acceleration
smaller
acceleration
At constant force, acceleration decreases as mass increases.
Newton's Second Law of Motion
Expression
force
F
a=
m
acceleration
OR
mass
F = ma
Practice Test
1. How fast will an 800kg car accelerate if it is
pushed with 4000N of force?
Practice Test
2. How fast will a 0.15kg hockey puck accelerate
if it is hit with 1.2 N of force?
Answer This!
1. Given a force of 100 N and an acceleration of
10 m/s2, what is the mass?
Answer This!
2. What is the acceleration of a 10 kg mass
pushed by a 5 N force?
Summary
Force and
Acceleration
At constant
mass,
acceleration
increases as
mass
increases.