Quiz on Newton's Third Law of Motion

What does Newton's Third Law of Motion state?

• For every action, there is an equal and opposite reaction.

• An object in motion stays in motion unless acted upon by an external force.

• Force equals mass times acceleration.

• Energy cannot be created or destroyed.

Answer explanation

Newton's Third Law of Motion states that for every action, there is an equal and opposite reaction. This means that forces always occur in pairs, with one force acting in one direction and the other in the opposite direction.

Which of the following is an example of Newton's Third Law?

• A car accelerating on a highway.

• A person pushing against a wall and the wall pushing back.

• A satellite orbiting the Earth.

• A ball rolling down a hill.

Answer explanation

Newton's Third Law states that for every action, there is an equal and opposite reaction. When a person pushes against a wall, the wall exerts an equal force back, exemplifying this law. The other options do not illustrate this principle.

In the context of Newton's Third Law, what are action-reaction force pairs?

• Forces that cancel each other out.

• Forces that act on the same object.

• Forces that only occur in space.

• Forces that are equal in magnitude and opposite in direction, acting on different objects.

Answer explanation

Action-reaction force pairs, as per Newton's Third Law, are forces that are equal in magnitude and opposite in direction, acting on different objects. This means they do not cancel each other out, as they act on separate entities.

How does Newton's Third Law apply to rocket propulsion?

• The rocket's engines push against the air to move forward.

• The rocket's shape reduces air resistance.

• The rocket's weight is reduced as it burns fuel.

• Exhaust gases are expelled downward, and the reaction force pushes the rocket upward.

Answer explanation

Newton's Third Law states that for every action, there is an equal and opposite reaction. In rocket propulsion, the rocket expels exhaust gases downward, creating a reaction force that propels the rocket upward.

What role does Newton's Third Law play in walking?

• It is irrelevant to walking.

• It explains why we need shoes.

• It shows how gravity affects our steps.

• It describes how the ground pushes back with an equal and opposite force when we push against it.

Answer explanation

Newton's Third Law states that for every action, there is an equal and opposite reaction. When we walk, our foot pushes down on the ground, and the ground pushes back with an equal force, allowing us to move forward.

Which of the following is NOT an application of Newton's Third Law?

• Rocket propulsion

• Walking or running

• Bouncing a basketball

• Photosynthesis in plants

Answer explanation

Photosynthesis in plants does not involve action-reaction pairs as described by Newton's Third Law. In contrast, rocket propulsion, walking, and bouncing a basketball all demonstrate this law through forces acting in opposite directions.

In a car crash, how does Newton's Third Law explain the forces involved?

• The larger car exerts a greater force.

• Only the faster car experiences a force.

• The forces cancel each other out completely.

• The cars exert forces on each other that are equal and opposite.

Answer explanation

According to Newton's Third Law, when two cars collide, they exert equal and opposite forces on each other. This means that the force the first car exerts on the second is matched by the force the second car exerts back on the first.

How is Newton's Third Law relevant in engineering and construction?

• It helps in designing structures that can float.

• It is not relevant to engineering.

• It is used to calculate the speed of construction.

• It ensures that forces exerted by structures are balanced by equal and opposite forces from the ground.

Answer explanation

Newton's Third Law states that for every action, there is an equal and opposite reaction. In engineering, this principle ensures that the forces exerted by structures are balanced by equal and opposite forces from the ground, maintaining stability.

What is the significance of Newton's Third Law in robotics?

• It allows robots to balance forces for precise movements.

• It is used to program artificial intelligence.

• It helps robots to generate energy.

• It is not applicable to robotics.

Answer explanation

Newton's Third Law states that for every action, there is an equal and opposite reaction. In robotics, this principle is crucial for balancing forces, enabling robots to execute precise movements effectively.

Why is Newton's Third Law considered fundamental in physics?

• It is a recent discovery in science.

• It is the only law that describes motion.

• It explains the interactions of forces in the physical world.

• It only applies to objects in space.

Answer explanation

Newton's Third Law is fundamental because it explains how forces interact; for every action, there is an equal and opposite reaction. This principle is crucial for understanding motion and forces in the physical world.