Question

Q.1 Assertion. The work done during a round trip is always zero.
Reason : No force is required to move a body in its round trip.
A) Both assertion and reason are true and the reason is the correct explanation of the assertion.
B) Both assertion and reason are true but reason is not the correct explanation of the
assertion.
C) Assertion is true but reason is false.
D) The assertion and reason both are false.
E) Assertion is felse bucreason is true.​

Answer 1

Assertion is true and Reason is false

Let's see a detailed explanation:

• The work done by a force with a displacement 'd' is given as:

$W = \vec{F}. \vec{d}$

$\implies W = | \vec{F}| \times | \vec{d} | \times \cos( \theta)$

For a round trip, the starting and the stopping point of the object will be same , hence the displacement of the object will be zero.

So, work done will be :

$\implies W = | \vec{F}| \times | \vec{d} | \times \cos( \theta)$

$\implies W = | \vec{F}| \times 0 \times \cos( \theta)$

$\implies W = 0$

• So, force is non-zero but displacement is zero. This contributes to zero work done in round trip.

So, option C) is correct ✔️