Section 2.2 Force and mass determine
acceleration.
• ___________________________ states that the acceleration of an object increases with increased force and decreases with increased mass.
Newton’s Second Law
Vocabulary
Which shopping cart will have more acceleration if the same force is applied to both carts?
small
mass
large
mass
same size force
same size force
greater acceleration smaller
acceleration
So… Increasing Mass Decreases Acceleration!
Which shopping cart will have more acceleration?
same
mass same
mass
greater acceleration smaller
acceleration
greater force
smaller force
So… Increasing Force Increases Acceleration!
An apple and a bowling ball are pushed with the same force. Which one will accelerate
more? Why?
The apple will accelerate more because it has less mass.
Calculating Force
F = maF = force
m = mass
a = acceleration
Calculating Force Class Example
• What force is needed to accelerate a 10 kg shopping cart 3 m/s2?
F = m x a
F = 10 kg x 3 m/s2
F = 30 N
Calculating ForcePractice Problem #1
• If a 5 kg ball is accelerating 1.2 m/s2, what is the force on it?
F = 5 kg x 1.2 m/s2
F = 6 N
Calculating ForcePractice Problem #2
• A person on a scooter is accelerating 2 m/s2. If the person has a mass of 50 kg, how much force is acting on that person?
F = 50 kg x 2 m/s2
F = 100 N
•Skip questions # 9-14
Thinking Question
• How can an object accelerate when it does not change speed?
It can simply change direction!
True or False?
• _____ A force can make an object change direction.
• _____ If an object only changes direction then it is not accelerating.
• _____ An object moves in the direction the force is applied.
• _____ Forces can cause acceleration.
True
True
True
False
Any force that keeps an object moving in a circle is known as _____________ force.
centripetal
Vocabulary
Where does the force point towards?
If you let go of the
string, the ball would
fly off in the direction
it was headed when
you let go. This is
called the path of
inertia.
What do the blue arrows
represent?
What do the
black
arrows
represent?
centripetal force
The path of inertia