E content

 Force

Learning outcome

After completing this lesson, the learner is expected:

-To define force and describe its effects on objects.

-To distinguish between contact and non-contact forces.

-To explain friction and illustrate its usefulness and disadvantages with examples.

-To demonstrate real-life situations where contact and non-contact forces are involved.

-To evaluate the advantages and disadvantages of friction in daily life scenarios.

Short note

Force is a fundamental concept in physics. It is defined as a push or pull acting upon an object with mass, which can change its velocity or direction of motion. Forces are broadly classified into Contact Forces (like friction, muscular force) and Non-contact Forces (like gravitational, magnetic, or electrostatic forces). Among these, friction plays a crucial role by opposing motion between two surfaces in contact — often helping us walk or hold things, though it also causes wear and tear.

Assessment Questions

Objective Type:

What is the SI unit of force?

a) Newton

b) Pascal

c) Joule

d) Watt

Answer: a) Newton

Friction is a:

a) Non-contact force

b) Balanced force

c) Contact force

d) Magnetic force

Answer: c) Contact force

Short Answer Type:

Define force and classify it.

What is friction? Mention two examples where friction is useful.

How is non-contact force different from contact force? Give one example each.

Higher Order Thinking (HOTS):

Is friction always harmful? Give your opinion with examples.