1. What we did in class today: Friday January 6th, 2012
Took notes over Newton’s 2nd & 3rd Laws
Demonstrations with the laws.
Reminder to study note cards and energy study guides for test week over Energy, metrics and scientific method on Tuesday.
Click on Physical Science
Go to Page 9
Metrics/scientific method
Mrs. Shafter’s Motion Vocabulary
Mrs. Shafter’s Electromagnetic Spectrum
Mrs. Shafter’s Waves

2. Unit C pgs. 49-55 (11.2) Force and Mass Determine Acceleration
Review 1. What stops the motion of a sled moving down a snowy hill?
The sled stops moving when acted
upon by an unbalanced force such
as friction.

3. I. Newton’s second law relates force, mass and acceleration.
2. Why is more force needed to accelerate a shopping cart
full of groceries than the same cart when its empty?
Because the mass of the shopping cart full of groceries has more
mass than the empty cart, more force is needed to accelerate
the full cart than the empty cart with the same acceleration.

4. A. Newton’s Second Law The mass of the object and
3. Write two factors that determine the acceleration of an object.
The mass of the object and
the size of the force applied.

5. the acceleration ______________________. increases
4. As you increase the force on an object,
the acceleration ______________________.
increases
As you increase the mass of an object,
the acceleration ___________________________.
decreases
the same as
The direction of acceleration is ______________________
the direction of the force.

6. B. Force Equals Mass Times Acceleration
5. Force = mass x acceleration
What force is needed to accelerate a 20 Kg wheelbarrow 4 m/s2 ?
Mass of wheelbarrow=
20 Kg
Acceleration of the wheelbarrow =
4 m/s2
Calculate the force.
F= 80N

7. 6. Acceleration = Force / mass
Zack pulls a loaded wagon with a force of 4N. If the wagon has a mass of 5 kg, what is its acceleration?
4 N
Force =
5 kg
mass =
.8 m/s2
Calculate the acceleration =

8. C. Mass and Acceleration
If you pushed a volleyball and a balloon with the same
force, explain which would have the greater acceleration.
The balloon would have the greater acceleration
because it has less mass than the volleyball.
Objects with less mass accelerate more.

9. II. Forces can change the direction of motion.
Applying a force to an object can result in three things. Complete the main idea
Chart with the three results of applying a force to a soccer ball.
Apply a force to a soccer ball.
The soccer ball may speed up
The soccer ball may slow down
The soccer ball may change direction

10. A. Centripetal Force
9. Draw a picture showing the meaning of centripetal force.
Draw an arrow to show the direction of the force.

11. B. Circular Motion and Newton’s Second Law
10. You grab a string with a ball attached to it and whirl
the ball in a circle over your head. In which direction
are you pulling the string? If you pull harder on the string,
what happens to the acceleration of the ball?
You are pulling the string toward the
Center of the circle.
The acceleration of the ball increases.

12. Unit C 11.3 Forces Act in Pairs
Highlight the Key Concept and Vocabulary
Mass and force.

13. As the bat meets the ball, it exerts a force upon it and
pushes the ball forward. The ball exerts an equal but
opposite force on the bat that pushes it backward.
The action force is the diver pushing down on the board.
The reaction force is the board pushing up on the diver.

14. Action and reaction forces act on different objects.
Action and reaction forces are equal and opposite.
Balanced forces act on a single object.
Balanced forces are equal
and opposite.

16. The rope will remain at rest until unbalanced forces act upon it (Newton’s first law). If the forces remain balanced, everyone will stay in the same place and the rope will
remain still. The forces are contact forces.
The four-member team will likely win the competition. Due to the extra team member, this side will be able to exert a greater force on the rope than the team with three
members (Newton’s second law).