Question

A ship of mass $3 \times 10^{7} k g$, initially at rest, is pulled by a force of $5 \times 10^{4} N$ through a distance of 3 m. Assuming that the resistance due to water is negligible, the speed of the ship is

• A. 1.5 m/s
• B. 60 m/s
• C. 0.1 m/s
• D. 5 m/s

Answer 1

Answer: (C)

Force, $F=m a$
$a=\frac{F}{m}=\frac{5 \times 10^{4}}{3 \times 10^{7}} m / s^{2}$
$\Rightarrow a=\frac{5}{3} \times 10^{-3} m / s^{2}$
Since, $v^{2}-u^{2}=2 a s$
$v^{2}-0=2 \times \frac{5}{3} \times 10^{-3} \times 3$
$v^{2}=10^{-2} v=0.1 m / s$