Question

Masses $m$ and $M$ on pulley move $0.6\, m$ in $4\, s$. What is ratio of $\frac{m}{M}$ ?

• A. $\frac{55}{57}$
• B. $\frac{113}{117}$
• C. $\frac{57}{55}$
• D. $\frac{397}{403}$

Answer 1

Answer: (D)

$\frac{397}{403}$

Answer 2

From $s=\frac{1}{2} a t^{2}$ $\Rightarrow a=\frac{2 s}{t^{2}}=\frac{2 \times 0.6}{(4)^{2}}$ $=\frac{3}{40}$ But $a=\left(\frac{M-m}{M+m}\right) g$ $\Rightarrow \frac{m}{M}=\frac{397}{403}$ (Take, $=10\, m/s ^{2}$)