Forces and Motion

A force between two objects that are touching.

• non-contact force

• motion

• contact force

• gravity

Change of position or place of an object.

• force

• motion

• speed

• gravity

A push or a pull.

• contact

• speed

• friction

• force

What would a student do to start a swing moving?

• Observe the swing

• Shorten the swing

• Push or pull the swing

• Measure the swing

Students create balloon rockets by taping drinking straws to balloons and running a thick string through the straw. The ends of the string are held tightly apart. When the balloon is inflated and released, it moves along the string. What should the students do to change the amount of friction that slows the motion of the balloon rocket?

• Try different color balloons.

• Use a different type of tape.

• Replace the string with thin wire.

• Hold the string ends closer together.

Shown are two magnets.

Which of the following best explains what magnet "B" will do if it is free to move.

• The force of gravity will pull it to the left.

• The magnetic force will pull it to the left.

• The force of gravity will push it to the right.

• The magnetic force will push it to the right.

A student drew the model car shown for a class project.

What was he most likely trying to model?

• The speed of a car

• The forces acting on a car

• The distance a car might move

• The things that change the size of the car

Students are racing model cars they designed and built. Which design improvement would most likely increase the speed of the car?

• Put oil on the nails on which the wheels turn to decrease the friction.

• Decrease the size of the wheels so they can grip better.

• Increase the size of the wheels so they can grip better.

• Put glue on the nails on which wheels turn to increase the friction.

2. By changing the surface over which the car rolls from sandpaper to wax paper, you might be able to test the effect of what force?

• A. Magnetism

• B. Wind

• C. Wind

• D. Friction

Which would require the most force to move?

• a toy car
• a sleeping cat
• a science book
• a chair with a friend sitting in it