Question

Two blocks $m_1=5\text{gm}$ and $m_2=10\text{gm}$ are hung vertically over a light frictionless pulley as shown here. What is the acceleration of the masses when they are left free?

(where $g$ is acceleration due to gravity)

• A. $\frac{g}{3}$
• B. $\frac{g}{2}$
• C. $g$
• D. $\frac{g}{5}$

Answer 1

The correct option is A $\frac{g}{3}$


Let $T$ be the tension in the string.

Applying Newton's seconds law on both the bodies,
$10g-T=10a$ ... (i)
$T-5g=5a$ ... (ii)
Adding (i) and (ii),
$5g=15a\Rightarrow a=\frac{g}{3}{\text{m/s}}^2$