Forces and Motion Quiz

Grade 6 · Science · Quiz

Test your knowledge of Newton's laws, friction, gravity, and how forces affect motion.

Questions

1. What is Newton's First Law of Motion also known as?

   1. The law of gravity
   2. The law of inertia
   3. The action-reaction law
   4. The acceleration law
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   Answer: The law of inertia

   Newton's First Law is called the law of inertia because it describes how objects resist changes in their state of motion.

2. A net force of zero means an object must be standing still.

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   Answer: False

   A net force of zero means no acceleration — the object could be still OR moving at a constant speed.

3. If you apply the same force to a 2 kg ball and a 10 kg ball, which accelerates more?

   1. The 10 kg ball
   2. The 2 kg ball
   3. They accelerate equally
   4. Neither one accelerates
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   Answer: The 2 kg ball

   From F = ma: with the same force, smaller mass means greater acceleration. a = F/m.

4. For every action, there is an equal and ___ reaction.

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   Answer: opposite

   Newton's Third Law: action and reaction forces are always equal in magnitude but opposite in direction.

5. Which force pulls objects toward the center of Earth?

   1. Friction
   2. Tension
   3. Magnetism
   4. Gravity
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   Answer: Gravity

   Gravity is the attractive force between masses. Earth's gravity accelerates objects downward at 9.8 m/s².

6. Friction is always a harmful force that should be eliminated.

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   Answer: False

   Friction is useful in many situations — it lets you walk, stops your car, and helps you hold a pencil.

7. A 5 kg object accelerates at 3 m/s². What is the net force on it?

   1. 2 N
   2. 8 N
   3. 15 N
   4. 1.67 N
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   Answer: 15 N

   F = ma = 5 kg × 3 m/s² = 15 Newtons.

8. The tendency of an object to resist changes in motion is called ___.

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   Answer: inertia

   Inertia is why you lurch forward when a car stops suddenly — your body wants to keep moving.

9. When you sit in a chair, the chair pushes back up on you with equal force. This illustrates:

   1. Newton's First Law
   2. Newton's Second Law
   3. Newton's Third Law
   4. The law of gravity
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   Answer: Newton's Third Law

   You push down on the chair (action) and the chair pushes up on you (reaction) with equal force.

10. On the Moon, objects fall slower than on Earth because the Moon has less gravity.

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    Answer: True

    The Moon's gravitational pull is about 1/6 of Earth's, so objects fall more slowly and weigh less on the Moon.

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