Question

The speed of the block when it reaches the point $Q$ is

• A. $10\sqrt{3}m{s}^{-1}$
• B. $20m{s}^{-1}$
• C. $10m{s}^{-1}$
• D. $5m{s}^{-1}$

Answer 1

The correct option is C $10m{s}^{-1}$

Applying mechnical energy theorem
$-150=-1\times 10\times \frac{40}{2}+\frac{1}{2}\times 1\times V^2$
$\Rightarrow V^2=100$
$\Rightarrow V=10\frac{m}{s}$