F= Ma

Presentation illustrating Newton's second law and centripetal force.

1. Force and mass determine
acceleration

• Newton’s second law
• Calculate force (F=ma)
• Force works in a circular motion

2. Newton’s second law
•The acceleration of an object increases with increased
force and decreases with increased mass
Small force
acceleration
larger force
acceleration
small mass
acceleration acceleration
larger mass

3. Newton’s second law
•Also states that the direction in which an
object accelerates is the same as the direction
of the force
force
acceleration

4. Calculating force
•Force= mass x acceleration
•F= ma

•Standard unit: newton (N)
- The amount of force it takes to accelerate
1 kg of mass 1 m/s
2

5. What force is needed to accelerate a
10 kg shopping cart 3 m/s ?
What do you know? m= 10 kg a= 3 m/s
What do you want to find out? Force
Write the formula: F= ma
Substitute the formula: F= 10 kg x 3 m/s
Calculate: F= 30 N
2
2
2

6. If a 5 kg ball is accelerating 1.2 m/s what is the force on
it?
F= ma
F= 5 kg x 1.2 m/s
F= 6 N
A person on a scooter is accelerating 2 m/s . If the
person has a mass of 50 kg, how much force is acting
on the person?
F= ma
F= 50 kg x 2 m/s
F= 100 N
2
2
2
2

7. Centripetal force
•Any force that keeps an object moving in a
circle
•Force points towards center of a circle
The force that keeps
the female skater
moving in a circle is
the pull exerted by her
partner

8. Summary
•Newton’s second law: Acceleration increases
with increased force; decreases with increased
mass. An object accelerates in the same
direction of the force.
•F= ma
•newton (N)
•Centripetal force: keeps an object going in a
circle.