Force and Motion

A soccer ball is kicked across a field and eventually comes to a stop. What is the primary reason for the ball stopping?

• a frictional force

• the strength of the kick

• the air resistance

• a gravitational force

The force diagrams show different forces acting on three different legos. How many blocks will experience a change in motion?

• 0

• 1

• 2

• 3

A group of students is tasked with demonstrating Newton’s third law of motion using a simple experiment. They choose to use a toy car and a balloon. When the student lets go of the straw the air will rush out and move the car. Which statement does NOT describe the forces?

• The action force is the balloon pushing air out, and the reaction force is the air pushed back on the balloon moving the car.

• The forces involved are equal in magnitude but opposite in direction.

• The car moves in the opposite direction as the air being released from the balloon.

• The reaction force is greater than the action force.

The sudden movement of the tectonic plates is caused by

• the mass of the plates

• balanced forces

• unbalanced forces

• gravitational force

A fish is swimming upstream against the current. The fish exerts a force of 25 newtons against the water, while the water pushes with a force of 10 newtons against the fish. Which statement best describes the fish's motion?

• The fish will be pushed backward by the current.

• The fish will remain stationary. (at rest)

• The fish will move forward against the current.

• The fish will move in the direction of the current.

What role does friction play in the movement of objects?

• It improves the force of gravity to increase motion.

• It can act without being in contact with an object.

• It acts upon contact with an object to resist its motion.

• It always stops an object completely by opposing all motion.

A boy is standing on a surfboard and facing North. If he jumps off the surfboard in the direction he is facing, which direction will the surfboard move?

• North

• South

• East

• West

A boy jumps off a surfboard to the left and the board goes to the right.

Which choice below explains why the surfboard moves the way it does?

• The law of action-reaction will cause the surfboard to move in the opposite direction of the jump.

• The law of action-reaction will cause the surfboard to move in the same direction as the jump.

• The law of gravity will force the surfboard to move south after the boy jumps.

• The law of gravity will cause the surfboard to move in the opposite direction of the jump.

What can be said about the forces acting on a ball resting on a table?

• The force of gravity is greater than the normal force exerted by the table.

• The normal force exerted by the table is greater than the force of gravity.

• No forces are acting on the ball because it is stationary. Forces only act on moving objects.

• The force of gravity pulling down on the ball is balanced by the normal force from the table pushing up. The ball remains at rest because the forces are equal.

Consider the following scenarios. Identify which of these scenarios involve balanced forces acting on an object. Select THREE correct answers.

• A book resting on a table.

• A cyclist accelerating down a hill.

• A satellite orbiting Earth at a constant speed.

• A ball rolling to a stop on a flat surface.

• A boat moving at a constant speed in a straight line.