Chapter 2: Forces Reinforcement Quiz

1. Friction acts in a direction __________ to the direction of an object's motion

Unrelated

Opposite

Equal

Perpendicular

Friction acts in the opposite direction to the direction of an object's motion. When an object is moving, friction opposes its motion by exerting a force in the opposite direction. This force acts to slow down or stop the object's movement. Friction is caused by the interaction between the surfaces of two objects in contact, and it always acts in a direction opposite to the object's motion.

Explanation

Friction acts in the opposite direction to the direction of an object's motion. When an object is moving, friction opposes its motion by exerting a force in the opposite direction. This force acts to slow down or stop the object's movement. Friction is caused by the interaction between the surfaces of two objects in contact, and it always acts in a direction opposite to the object's motion.

2. Jake and Tom want to see who is strogest, so they got a rope and decided to play tug-o-war. Both boys pulled at the rope with all of their strength, but neither of them moved. Since neither was able to move the other. These forces are said to be unbalanced.

True

False

When forces equal each other. Then the net force is zero which means they are BALANCED!

Explanation

When forces equal each other. Then the net force is zero which means they are BALANCED!

3. A (n) ______________ can cause an objects motion to change

Unbalanced force

Balanced force

Inertia

Mass

An unbalanced force refers to a force that is not equal in magnitude and opposite in direction to another force. When an unbalanced force acts on an object, it causes a change in the object's motion. This change can be in terms of speed, direction, or both. In contrast, a balanced force refers to forces that are equal in magnitude and opposite in direction, resulting in no change in the object's motion. Inertia and mass are properties of an object that determine its resistance to changes in motion, but they do not directly cause the motion to change.

Explanation

An unbalanced force refers to a force that is not equal in magnitude and opposite in direction to another force. When an unbalanced force acts on an object, it causes a change in the object's motion. This change can be in terms of speed, direction, or both. In contrast, a balanced force refers to forces that are equal in magnitude and opposite in direction, resulting in no change in the object's motion. Inertia and mass are properties of an object that determine its resistance to changes in motion, but they do not directly cause the motion to change.

4. On which type of surface would a soccer ball roll the farthest?

Sandy Beach

Grassy Lawn

Carpeted Floor

Marble Floor

The Marble floor will be the smoothest surface; therefore, it will have the least amount of friction. Less friction means the ball will continue to move for a longer period of time and distance.

Explanation

The Marble floor will be the smoothest surface; therefore, it will have the least amount of friction. Less friction means the ball will continue to move for a longer period of time and distance.

5. Frictional forces act in the same direction as the motion of the object.

True

False

Friction always opposes the direction of the motion. It slows the object down.

Explanation

Friction always opposes the direction of the motion. It slows the object down.

6. A hockey puck is sliding across the ice. Friction would be acting to increase the speed of the puck.

True

False

The puck would be slowed by the forces of friction.

Explanation

The puck would be slowed by the forces of friction.

7. Match the following

Kinetic Friction

Static Friciton

Fluid Friction

Rolling Friction

Lubricant

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8. Which of the following would be a harmful effect of friction?

Using brakes to stop your bicycle.

Sliding across the rug and getting a rug burn on your leg.

Rubbing your hands together to keep them warm

Using the eraser on your pencil to correct your test mistake

Only sliding on the rug and getting a rug burn would be a harmful affect of friction. The other choices are all helpful uses of friction.

Explanation

Only sliding on the rug and getting a rug burn would be a harmful affect of friction. The other choices are all helpful uses of friction.

9. Which of the following statements are true? Choose all that apply.Frictional forces are increased when

Increased force is added to press the objects closer together.

Surfaces objects are smoother

Surfaces of the objects are rougher

Wheels are added to one of the objects in contact with the other.

Smoothing the surface and adding wheels will reduce friction; not increase it.

Explanation

Smoothing the surface and adding wheels will reduce friction; not increase it.

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10. Which of the following is a helpful increase in friction?

Adding chains to tires in the winter time for better traction in the snow and ice

Adding Salt to and icy sidewalk

Adding oil to a car's engine

Using wheels on a cart

Both adding chains and adding salt will increase the friction and make it easier to drive or walk

Explanation

Both adding chains and adding salt will increase the friction and make it easier to drive or walk

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