1. Give pairs of students a golf ball and a ruler.
2. Have them do this on the floor. Warn them about inappropriate actions
3. Have them pull back the ruler and strike the ball with a small force Demonstrate
4. Have them do it again with a larger force
5. Have them write in their journals the answer to these questions
6. How does changing the force of the ruler against the ball affect the motion of the ball?

Items Used , toy dump truck, spring balance

1. Follow the steps in the book
2. Have them write in their Journal "How did changing the mass of a loaded truck affect how it moves?'

Go over "Guide for Reading" and "Reading Strategies" p. 52M

Objectives: The student will be able to…

• Explain how force and mass are related to acceleration.

• Have students read pp. 52-54
• Discuss how the first two example the golf ball and truck are related. Tie in as a review to inertia.
• Newton's second law of motion explains how force, mass, and acceleration are related.
• Newton's 2^nd Law States that: The net force on an object is equal to the product of its acceleration and its mass.
• What is a Net Force?
• The formula is Force =Mass X Acceleration
• What is Mass? Weight?
• What does mass =? Force/acceleration
• What does acceleration =?force/mass
• Note the Units a= m/s/s mass=kg force=kg X m/s/s
• Force is measured in Newtons = a kg*m/s/s
• Explain how the m/s/s related to why you could pull the paper out from under an object when you did it fast but not when you did it slow. Force over time Impulse
• That is also why with enough acceleration a person can break a brick or a board with his hand.

1. Change weight to kg 2.2 lbs/kg
2. Acceleration due to gravity 9.8 m/s/s

1. Do example problem on the board using the steps
2. Have them do samples 1 and 2 on page 53

Show that a spring scale is often measured in newtons. Put a I kg mass on it to show them what it feels like tell them this is almost 10 N show on the board how you get it.

Changes In Force and Mass p. 54

1. Tie in to Newton's scooters
2. How can you increase the acceleration of your Newton's scooter to get it to go further? Lower the mass, increase the force against is or that it pushes with.

• First push it using the lightest kid in the class
• Then push it using the biggest person in the class. (Changing mass changes the ability to accelerate).
• Have a small person push the chair with a large person in it
• Have large person push the chair with a large person in it. (the force applied has an affect on acceleration).