1. Newton’s first law REVIEW
Summarize what the law states. What does an object at rest need for it to move? What is another name for newton’s first law of motion? What is inertia? What causes a moving object to stop moving? The (more/less) mass an object has, the harder it is to move.

2. Newton’s Second Law

3. NEWTON’S second law
The acceleration of an object depends on the mass of the object and the amount of force applied. VOLUNTEERS!!!!! TWO “pushers” of similar size ONE small 8th grader ONE big 8th grader
Have the “small” and “big” student sit in a chair. Have the “pushers” push them across the room. Discuss which required more energy and why.

4. Part 1: Acceleration depends on mass
Acceleration of an object decreases as its mass increases Acceleration of an object increases as its mass decreases
Which would be easier to push?
WHY?

5. Part 2: Acceleration depends on force
Acceleration of an object increases as the force on it increases Acceleration of an object decreases as the force on it decreases
VOLUNTEERS!!!!!
ONE to sit in chair
ONE to push chair

6. Newton’s law with MATH Force acceleration mass Formula: a = F m
Have students guess what the variables represent
UNITS 
accleration: m/s² (meters per second squared)
force: N (Newtons)
mass: kg (kilograms)

7. Tricky…tricky….
You don’t use newtons to find acceleration in this formula
1 N = 1 kg∙m/s²
So…4 N = 4 kg∙m/s²
And….500 N = 500 kg∙m/s²
And 395 N = ?

8. Newton and math example
Mass of apple: 0.102kg Force: 1N Acceleration? a= 1 kg∙m/s² (1N)/ 0.192kg a= 9.8 m/s

9. Practice
What is the acceleration of a 3kg mass if a force of 14.4 N is used to move the mass?
Have 2 students come to smart board and complete problem as a team

10. Practice
What is the acceleration of a 7kg mass if a force of 68.6 N I used to move it toward earth?

11. Challenge question
What force is necessary to accelerate a 1,250kg car at a rate of 40 m/s² ? HINT: F = m x a
Let a couple students try to figure it out before using the hint

12. Another challenging question
Zookeepers carry a stretcher that holds a sleeping lion. The total mass of the lion and the stretcher is 175 kg. The lion’s forward acceleration is 2 m/s². what is the force necessary to produce this acceleration?

13. Newton’s Laws video clip
eYPi2FU