Question

A ship of mass $3\times {10}^7$ kg 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. 0.1 m/s
• B. 1.5 ms
• C. 5 m/s
• D. 60 m/s

Answer 1

The correct option is A 0.1 m/s

1) $a=\frac{F}{m}=\frac{5\times {10}^4}{3\times {10}^7}=\frac{5}{3}\times {10}^{-3}m/s^2$

2) $2as=v^2-u^2$

$2\times \frac{5}{3}\times {10}^{-3}\times 3=v^2-0^2$

$\Rightarrow {10}^{-2}=v^2$

$\Rightarrow v=0.1m/s$