Question

Velocity of a particle of mass $10\text{kg}$ is increased from $30\text{m/s}$ to $40\text{m/s}$. What is the work done on it?

• A. $7000\text{J}$
• B. $1750\text{J}$
• C. $3500\text{J}$
• D. $1350\text{J}$

Answer 1

The correct option is C $3500\text{J}$

We know that, work done on it is given by change in its kinetic energy.

$W=\Delta KE=K{E}_f-K{E}_i$

$\Rightarrow W=\frac{1}{2}m{v}^2-\frac{1}{2}m{u}^2=\frac{1}{2}m(v^2-u^2)$

$\Rightarrow W=\frac{1}{2}\times 10\times ({40}^2-{30}^2)$

$\Rightarrow W=3500\text{J}$