Question

A body of $5kg$ is moving with a velocity of $20m/s$. If a force of $100N$is applied on it for $10s$ in the same direction as its velocity, what will now be the velocity of the body

• A. $200m/s$
• B. $220m/s$
• C. $240m/s$
• D. $260m/s$

Answer 1

The correct option is B

$220m/s$

Step 1. Given data

Mass of body,$m=5kg$

The initial velocity of the body, $u=20m/s$

Force applied, $F=100N$

Time for which force was applied,$t=10s$

Step 2. Velocity of body

The force is given by

$$\begin{gathered} F=ma \\ \Rightarrow 100=5\times a \\ \Rightarrow a=20m/s^2 \end{gathered}$$

$a$is acceleration on the body due to force $F$

Using newtons equation of motion, we find the final velocity $v$

$$\begin{gathered} v=u+at \\ \Rightarrow v=20+20\times 10 \\ =220m/s \end{gathered}$$

Hence, option B is correct.