1. Day 3 – Free body diagrams
Mr. Lambert
Integrated Science 1A
Trimester 1, 2014

2. Bell Ringer
Draw a free body diagram of a hockey puck as it slides across the ice.

3. Agenda Bell Ringer Practice Force problems
Retake Newton’s Second Law quiz
Exit Slip

4. Learning Targets
On your Bell Ringer Sheet, write the following: We will use free body diagrams to explain changes in motion.

5. Handout rubric

6. An airplane is flying across the sky. It is accelerating to the left.
1. Draw two free body diagrams of the forces that act on the airplane, one when it is at rest, and one when it is traveling.

7. Contrast the forces in the free body diagram
Contrast the forces in the free body diagram. How do the differences in the forces from the first FBD to the second FBD explain the change in motion of the airplane?
The first FBD shows only gravitational force and normal force, which are balanced. Therefore, there is no net force and the airplane does not accelerate.
The second FBD shows an engine force, air resistance force, lift force, and gravity force. The lift and gravity force cancel each other out, while the engine force and air resistance force are unbalanced. Since the engine force is greater, there is a net force and the airplane accelerates.

8. Predict how adding more passengers to the airplane will affect its motion. Use Newton’s Second Law to explain why.
Adding more passengers increases the mass of the airplane. If the force (engines) of the airplane stays the same, it will have a slower acceleration.

9. Predict how adding a more powerful engine will affect the motion of the airplane.
The more powerful engine will increase the force that moves the airplane. If the mass of the airplane stays the same, this will cause it to have a faster acceleration.

10. What is Newton’s Second Law?
Force = Mass x Acceleration (F = ma)
Shows the relationships among force, mass, and acceleration

11. Groups Your group will receive a sheet with a possible student answer on it. You need to score it based on the rubric, and explain why you gave it that score.

12. Draw a free body diagram of a hybrid car before it begins to move.
Draw a free body diagram of a hybrid car as it accelerates to the right.
Compare and contrast the forces in the free body diagrams above. How do the differences in the forces from the first FBD to the second FBD explain the change in motion of the hybrid car?

13. Try your own!
Based on the example we did in class, practice answering a question on your own before you retake the quiz!

14. A speedboat is floating at rest in the lake
A speedboat is floating at rest in the lake. The speedboat then begins to accelerate and race through the water.
Draw two free body diagrams of the forces acting on the speedboat, one when it is at rest, and one when it is accelerating.
Contrast the forces in the free body diagrams above. How do the differences in the forces from the first FBD to the second FBD explain the change in motion of the speedboat?

15. Use Newton’s Second Law to answer the following questions:
If you add more passengers to the speedboat, how does this affect its motion?
If the wind pushes in the same direction the speedboat is traveling, how does this affect its motion?

16. Fix your quiz!

17. Exit Slip
I am trying to push a big block of stone, but it is not moving. Use the following words to explain why the block is not moving:
Net force
Balanced or Unbalanced
Acceleration
Friction
Applied Force