Question

A force of 18 N is acting in the direction of motion of a body of mass 3 kg moving with a velocity of 2 ms\(^{-1}\). The velocity of the body when it displaces by 5 m is

• A. 4 ms\(^{-1}\)
• B. 6 ms\(^{-1}\)
• C. 10 ms\(^{-1}\)
• D. 8 ms\(^{-1}\)

Hint:

Use \( v^2 = u^2 + 2as \) when initial velocity, acceleration, and displacement are known.

Answer 1

The Correct Option is D

Step 1: Acceleration \( a = \frac{F}{m} = \frac{18}{3} = 6\ \text{ms}^{-2} \) Step 2: Use the equation of motion: \[ v^2 = u^2 + 2as = 2^2 + 2 \times 6 \times 5 = 4 + 60 = 64 \Rightarrow v = \sqrt{64} = 8\ \text{ms}^{-1} \]