Different Positions of a Rolling Ball

A student pushes a ball along a hallway. The diagram shows the position of the ball every second for five seconds after it starts rolling. At one of the positions shown, an extra force is applied to the ball as it moves. Which position of the ball BEST represents the direction of the extra force and the position where the extra force was applied to the ball?

• Position 2 (arrow pointing right)

• Position 3 (arrow pointing right)

• Position 4 (arrow pointing left)

• Position 5 (arrow pointing right)

Students build a balloon-rocket car using a balloon, a straw, a water bottle, and some tape. When the straw is released by a student, the air from the balloon comes out. A diagram of the car is shown. Which statement best describes the motion of the car when the straw is released?

• The car will move away from the wall in the same direction as the air that is leaving the balloon.

• The car will move toward the wall because of the force of the air from the straw.

• The car will move fast because the straw gets light as the air is released.

• The car will not move because the air escapes from the balloon.

A wagon is pushed and begins to move. As the wagon moves, it slows and comes to a stop. The wagon and the direction it is pushed are shown. What force causes the wagon to stop?

• The force of gravity which is acting in the same direction as the arrow

• The force of friction which is acting in the same direction as the arrow

• The force of gravity which is acting in the opposite direction of the arrow

• The force of friction which is acting in the opposite direction of the arrow

Students fill a cart with books. The cart has a handle on each end. Which actions will make moving the cart in one direction easiest for the students?

• Student 1 pulls the cart to the left while Student 2 pulls the cart to the right.

• Student 1 pulls the cart to the left while Student 2 pushes the cart to the left.

• Student 1 pushes the cart to the right while Student 2 pushes the cart downward.

• Student 1 pushes the cart to the right while Student 2 pulls the cart upward.

What is the athlete demonstrating in the picture?

• Doing work by pushing the ball and changing its motion and position

• Changing the position but not the motion of the ball

• Doing work by pulling the racquet and changing the ball’s position but not its motion

• Changing the position and motion of the ball without doing any work

Four students stand facing a box. The diagram below shows an overhead view of the box. The numbered circles represent the positions of the students. What do the students need to do to slide the box to the northeast?

• Students 1 and 2 push, and Students 3 and 4 pull.

• Students 1 and 4 push, and Students 2 and 3 pull.

• Students 2 and 3 push, and Students 1 and 4 pull.

• Students 3 and 4 push, and Students 1 and 2 pull.

The diagram below shows a view of a ball from above a table. The ball is rolling across the table. A student lightly taps the rolling ball in the direction shown below. In which direction does the ball most likely move after the student taps the ball?

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Students conduct experiments to investigate friction. Which experiment will best test the effect of friction on objects?

• Drop two balls from the same height at the same time

• Roll two marbles on the carpet from the same starting point at the same time and with the same amount of force

• Roll three marbles across three different surfaces from the same starting point at the same time and with the same amount of force

• Release two balls from the top of a ramp at the same time

A student conducts the investigation shown in the diagram. In this experiment a paper cup hangs from a string tied to a single uncooked spaghetti noodle. The student measures and records the mass of a penny. The student then adds pennies to the paper cup one at a time.

• How many spaghetti noodles will it take to hold up the mass of a penny?

• How much force will it take to break the spaghetti noodle?

• How long should the string that holds the paper cup be in order to support the greatest mass of pennies?

• How does the distance between the two chairs affect the amount of force it takes for the spaghetti noodle to break?

The diagrams show two trials of an experiment in which a spring scale was used to measure force. Trial 1: A spring scale is attached to a 1 kg dictionary. Trial 2: A spring scale is attached to a 1 kg dictionary with a 2 kg box of marbles on top. This experiment can be used to determine —

• how mass affects the force needed to move objects

• how force affects the mass of two objects

• how the force used to pull a dictionary affects the mass of a box of marbles

• how the mass of a box of marbles affects the mass of a dictionary