1. Newton’s 2nd Law of Motion

2. Acceleration- the change in velocity that objects experience over time
Rate of change in velocity
Vector
Changing either speed or direction changes acceleration
Units: m/s² or m/s/s

3. Finding Acceleration Acceleration= change in velocity time
Change in velocity = final – initial velocity velocity
Acceleration= final velocity- initial velocity time
A = Vf - Vi

4. A car traveling at 60 m/s accelerates to 90 m/s in 3 seconds
A car traveling at 60 m/s accelerates to 90 m/s in 3 seconds. What is the car’s acceleration?

5. Deceleration- something slows down ( negative acceleration)
A car traveling at 60 mph slams on the breaks to
avoid hitting a deer. The car comes to a safe stop
6 seconds after applying the breaks. What is the
car’s acceleration?

6. Free Fall: the constant acceleration of an object moving only under the influence of gravity is g =9.8 m/s2
The acceleration caused by gravity is 10 m/s2
If there was no air, all objects would fall at the same speed
Doesn’t depend on mass
After 1 second falling at 10 m/s
After 2 seconds 20 m/s
3 seconds 30 m/s

7. Gravity…

8. Acceleration is caused by a FORCE
Acceleration is always in the same direction of the net force
Acceleration is directly proportional to force.

9. Acceleration also depends on Mass.

10. Acceleration also depends on mass
Mass: measure of how much material an object has
Weight: depends on the amount of gravity
Mass is not the same thing as weight!!!

11. Weight vs. Mass

12. More mass an object has the less acceleration
Acceleration ~1/ mass
Acceleration is inversely proportionate to mass

13. Newton’s 2nd law
The acceleration produced by a net force on an object is directly proportional to the net force, is in the same direction as the net force and is inversely proportional to the mass of an object
F=ma

14. What?? The larger the net force, the bigger the acceleration.
Acceleration and net force are always in the same direction.
The larger the mass the smaller the acceleration.

15. Practice Problems
Consider a 1000kg car pulled by a cable with 2000N of force. What would be the acceleration?

16. One more problem
If a mass of 5kg is moving at an acceleration of 3 m/s2, what is the force?