Lesson 3: Effects of Forces Quiz

Michael and Aria are pushing a box from opposite sides. The net force on the box is found by

• adding the forces.

• dividing the forces.

• subtracting the forces.

• multiplying the forces.

Answer explanation

The net force on the box is determined by adding the forces exerted by Michael and Aria. Since they are pushing from opposite sides, their forces combine to create a total force acting on the box.

Abigail and Aiden are pushing a box together. Abigail applies a force of 15 N, and Aiden applies a force of 30 N. What is the net force acting on the box?

• 2 N

• 15 N

• 45 N

• 450 N

Answer explanation

The net force is the sum of the forces applied by Abigail and Aiden. 15 N + 30 N = 45 N. Therefore, the net force acting on the box is 45 N.

Jackson and Mason are pushing a box from opposite sides. To find the net force on the box, they should calculate it by

• adding the forces.

• dividing the forces.

• subtracting the forces.

• multiplying the forces.

Answer explanation

To find the net force on the box, Jackson and Mason should subtract the force exerted by one from the other. Since they are pushing from opposite sides, their forces oppose each other.

When Harper applies the brakes on her bicycle while going downhill, it is an example of

• the net force on an object being positive.

• the net force on an object slowly increasing.

• the net force an object remaining the same over time.

• the net force on an object being equal to one force on the object.

Answer explanation

When Harper applies the brakes, the force of the brakes opposes her motion, resulting in a net force that is equal to the braking force. This demonstrates that the net force on the object is equal to one force acting on it.

Mason is pushing a shopping cart at the grocery store. Finding the net force on the cart is useful because

• you can predict the direction of the cart.

• you can predict the next force that will act on the cart.

• it allows you to predict whether the cart’s motion will change.

• you can tell how the forces acting on the cart have changed over time.

Answer explanation

Finding the net force on the cart helps determine if its motion will change. If the net force is not zero, the cart will accelerate, indicating a change in motion.

David and Harper are pushing a box from opposite sides. The difference between balanced and unbalanced forces in this scenario is that

• balanced forces are multiples of 5 N, while unbalanced forces are not.

• balanced forces have a net force equal to 0 N, while unbalanced forces do not.

• balanced forces have a net force unequal to 0 N, while unbalanced forces are equal to 0 N.

• balanced forces have multiple forces that are equal to the same number, while unbalanced forces do not.

Answer explanation

In this scenario, balanced forces result in a net force of 0 N, meaning the forces are equal and opposite. Unbalanced forces, however, lead to a net force that is not zero, causing movement or acceleration.

William is pushing a shopping cart in a grocery store. Which of the following is NOT a component of Newton’s first law of motion?

• An object at rest stays at rest.

• An object in motion stays in motion.

• An object in motion has a constant velocity unless acted on by a balanced force.

• An object in motion has a constant velocity unless acted on by an unbalanced force.

Answer explanation

The correct choice is 'An object in motion has a constant velocity unless acted on by an unbalanced force.' This statement is incorrect because it implies that balanced forces can change motion, which contradicts Newton's first law.

Zoe places a book on a table, and it remains at rest. The net force on the book

• is always 0 N.

• changes depending on the location of the book.

• is the result of unbalanced forces acting on the book.

• depends on the balanced forces acting on the book.

Answer explanation

The book remains at rest, indicating that the net force acting on it is 0 N. This means all forces are balanced, confirming that the correct answer is 'is always 0 N.'

Ava is riding her bicycle on a flat road. What is most likely to happen to her bicycle if the net force acting on it is 0 N?

• It will likely accelerate.

• It will slowly come to a rest.

• It will come to a complete stop.

• It will continue to move with the same velocity.

Answer explanation

If the net force on Ava's bicycle is 0 N, it means there is no unbalanced force acting on it. According to Newton's first law, the bicycle will continue to move with the same velocity.

Grace is riding her bicycle at a constant speed on a flat road. What is most likely to happen to her bicycle if an unbalanced force acts on it?

• It will likely accelerate.

• It will slowly come to a rest.

• It will come to a complete stop.

• It will continue to move with the same velocity.

Answer explanation

An unbalanced force acting on Grace's bicycle will cause it to change its state of motion. Since she is riding at a constant speed, the bicycle will likely accelerate in the direction of the force.