Force and Motion Assessment

What happens to an object that is already moving if you add to the net force already acting on the object?

• It will speed up.

• Its motion does not change.

• It will stop moving.

• It will slow down.

Which pair of objects will have the LEAST gravitational attraction to each other?

• Two cinder blocks 6 centimeters apart.

• Two marbles 12 centimeters apart.

• A cinderblock and marble 6 centimeters apart.

• A cinderblock and marble 12 centimeters apart.

Which conclusion can you draw from the data presented in the table above?

• As an object falls to the ground, its acceleration changes due to gravity.

• The acceleration due to gravity is constant and has a value of 9.8 m/s².

• Heavier objects fall to the ground faster than lighter objects.

• Gravitational attraction does not affect the acceleration of an object.

According to the diagram, the block should be moving in which direction?

• The block should not move at all.

• The block should move to the left.

• The block should move to the right.

• There is no way to tell which way the block should move.

Which of the following statements is TRUE if a moving object is slowing down?

• A. A force within the object must be decreasing.

• B. A force that is pulling or pushing the object forward must be decreasing.

• C. A force that is causing the object to slow down must be increasing.

• D. A force that is causing the object to slow down must be greater than the sum of the forces that are pulling or pushing the object forward.

Which of the following is an example of changing acceleration?

• A train traveling 65 miles per hour south

• A boat sailing west at 5 knots

• A person jogging at 3 meters/second along a winding path

• A car stopped at a red light

Newton's second law states that F = m x a (Force is mass times acceleration). Which example would have the GREATEST acceleration?

• a 10 kg ball thrown with a 50 Newton force

• a 1 kg ball thrown with a 0.5 Newton force

Which of the following statements is TRUE about the motion of a cart that is being pushed on a level surface?

• The cart is moving at constant speed if the force of the push is constant and less than the force of friction on the cart.

• The cart is moving at constant speed if the force of the push is constant and is greater than the force of friction on the cart.

• The cart is moving faster and faster if the force of the push is constant and is greater than the force of friction on the cart.

• The cart is moving faster and faster if the force of the push is constant and the same strength as the force of friction on the cart.

Could the box move faster than the man is walking?

• A. Yes, but only if he didn't walk fast.

• B. Yes, but only if he pushed the box harder and harder.

• C. Yes, but only if the force of the push on the box was greater than the force of friction on the box.

• D. No, because if he was pushing with constant force, the box would have to move at constant speed.

In the fable of the tortoise and the hare, the tortoise eventually wins the road race over the fast-running hare. As an observant science student, the data table gives several clues to the tortoise’s win. Read the explanations below and pick the explanation that BEST fits the data.

• The hare never changed his speed throughout the race.

• The hare took shorter rest stops during the race than the tortoise did.

• The hare had a constant rate of acceleration throughout the race; the tortoise stopped to rest.

• The tortoise moved at a constant velocity throughout the race; the hare stopped to rest periodically.