Question

A boy is running in a circular path of radius 70 m. If he completes a round in 10 min. Then the velocity of the boy after completing one round of the circular path is:
1. Zero
2. 44 m/s
3. 0.73 m/s
4. 1 m/s

Answer 1

Correct Answer - Option 1 : Zero

CONCEPT:

Velocity:

• Velocity is defined as the displacement covered by a body in unit time.
• Velocity is a vector quantity.

​\(⇒ v=\frac{dx}{dt}\)

Where dx = displacement, and dt = time

Displacement

• It is the shortest distance between the initial and final position of the particle.
• It is a vector quantity.

CALCULATION:

Given r = 70 m, and dt = 10 min = 600 sec

• When a boy completes one round of the circular path, he will reach the initial point from where he starts.
• So his displacement will be zero.

⇒ dx = 0

Therefore velocity of the boy in completing one round is,

\(⇒ v=\frac{dx}{dt}\)

\(⇒ v=\frac{0}{600}\)

⇒ v = 0 m/s

• Hence, option 1 is correct.