Kennedy CFA1

A teacher leaves a coffee mug on top of a car, as shown in the diagram below. The teacher drives the car in a straight line and then stops suddenly. What happens to the coffee mug when the car stops?

• The mug moves forward.

• The mug moves backward.

• The mug moves side to side.

• The mug stays in the same position.

Two people are each pulling on the opposite ends of a rope. If they are pulling on the rope with equal but opposite forces, what will happen to the rope?

• It will stay in place between the two people.

• It will move toward the right.

• It will move toward the left.

• It will fall to the ground.

Which situation is explained by Newton’s first law of motion?

• A basketball bounces upward when it is dropped on the floor.

• You can lift more mass with the same force using a longer lever.

• Even though you stop pedaling your bicycle, you keep moving forward.

• More fuel is required to accelerate a large truck than is required to accelerate a small car.

A performer pulls a tablecloth out from under a complete set of dinnerware as shown in the illustration below. (8.PS2.3)

• The inertia of the dinnerware

• The large mass of the tablecloth

• The placement of the dinnerware

• The rough material of the tablecloth

Jeannie put her soccer ball on the ground on the side of a hill. Which force acted on the soccer ball to make it roll down the hill? (8.PS2.2)

• Gravity

• Electricity

• Friction

• Magnetism

Which action makes the car move forward?

• A push on the back of the car

• A push on the front of the car

• A push on the side of the car

The illustration below shows a 2-ton elephant balancing on a tree stump. Which of the following statements must be accurate?

• The weight of the tree stump is greater than 2-tons.

• A 4-ton force on the ground spreads out in all directions.

• The tree stump is exerting a 2-ton force upward on the elephant.

• The downward force on the tree stump is 4-tons.

The picture below shows a student pulling on a rope that is attached to a wall. (8.PS2.2)

• The wall pulls with a force of 125-newtons against the student.

• The wall pulls with a force of 250-newtons against the student.

• The wall exerts twice as much force as the student.

• The wall exerts no force since it is stationary.

Chang jumps rope. No matter how high he jumps, he still returns to the ground. What force pulls him back to the ground? (8.PS2.2)

• Inertia

• Gravity

• Friction

• Pressure

Students learned that objects can exert forces on other objects without touching. (8.PS2.2) Which three investigations will provide evidence to support what they have learned?

• measuring how close a soda can must be before it rolls toward a balloon that has been rubbed on someone’s hair.

• counting the number of staples that are directly attached to a strong magnet.

• dropping a rubber ball from a distance of 1.5 meters above the classroom floor.

• placing a magnet against a jar containing a mixture of iron filings and sand.

• measuring how far a toy car travels across the floor before coming to a stop.