Exploring Forces — Class 8 MCQs with Answers

Exploring Forces — important questions & MCQs with answers (Class 8 Science)

6 solved questions from this chapter's difficulty levels, each with its answer and explanation. Tap an option to check yourself.

0 of 6 answered

1. Q1 of 6Easy

   A force is a:

   Apush or a pullBonly a pushConly a pullDa colour
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   Answer: push or a pull

   Explanation: A force is any push or pull an object exerts on another — never only a push or only a pull, since both directions count as forces, and it certainly isn't a colour or other property.

2. Q2 of 6Easy

   Forces that act only when objects are in contact are called:

   Anon-contact forcesBcontact forcesCmagnetic forcesDgravity
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   Answer: contact forces

   Explanation: Contact forces act only when two objects are physically touching, like a push or friction. Non-contact forces such as gravity or magnetism act without any touching at all.

3. Q3 of 6Medium

   Which of these is a non-contact force?

   Amuscular forceBgravitational forceCfrictionDa normal push
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   Answer: gravitational force

   Explanation: Gravitational force acts across empty space without the objects touching, making it a non-contact force. Muscular force, friction, and a normal push all require direct contact.

4. Q4 of 6Medium

   An object thrown upward comes back down because of:

   AfrictionBgravitational forceCa magnetic pullDmuscular force
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   Answer: gravitational force

   Explanation: An object thrown upward slows, stops, and falls back down because the Earth's gravitational force continuously pulls it downward, overcoming its initial upward motion.

5. Q5 of 6Hard

   A book resting on a table does not move because the forces on it are:

   Aunbalanced upwardBonly downwardCbalancedDmagnetic
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   Answer: balanced

   Explanation: A book resting on a table stays still because the table's upward push exactly balances the book's downward weight — balanced forces mean no change in the object's state of motion.

6. Q6 of 6Hard

   Which set lists only contact forces?

   Agravity and magneticBmuscular and frictionCelectrostatic and gravityDmagnetic and friction
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   Answer: muscular and friction

   Explanation: Muscular force and friction both require the objects involved to be touching, making them contact forces. Gravity, magnetism, and electrostatic force instead act without any contact.

Exploring Forces notes: key concepts (Class 8 Science)

This chapter explores forces — the pushes and pulls that shape the motion of everything around us. A force is measured in newtons and can change an object's speed, its direction of motion, or its shape; when forces cancel out they are balanced. Forces are contact forces (muscular force and friction, which act only on touching) or non-contact forces (magnetic, electrostatic and gravitational, which act across a gap). Gravity is the Earth's attractive pull, and the weight of an object is simply the gravitational force on it, measured in newtons.

Force

A push or a pull on an object, arising from its interaction with another object; its SI unit is the newton (N).

Effects of a force

A force can change the speed of a moving object, change its direction of motion, or change its shape.

Balanced forces

When two or more forces on an object cancel each other out, they are balanced and the object's state of motion does not change.

Contact forces

Forces that act only when objects are touching, such as muscular force and friction.

Muscular force

The force applied by muscles when they contract; living beings use it to push, pull and lift, and even to move food inside the body.

Friction

A contact force that opposes the motion of one surface over another; it is greater on rough surfaces and is reduced by smoothing or oiling.

Non-contact forces

Forces that act without the objects touching, such as magnetic, electrostatic and gravitational forces.

Magnetic force

A non-contact force of a magnet: like poles (N–N, S–S) repel while unlike poles (N–S) attract.

Electrostatic force

A non-contact force between charged objects; rubbing certain materials charges them, a charged object attracts light uncharged objects, and like charges repel.

Gravitational force

The Earth's pull on objects towards its centre; it is always attractive and keeps us on the ground.

Weight

The gravitational force with which the Earth pulls an object; since it is a force, it is measured in newtons and can differ from one object to another.