Question

ship of mass $2 \times 10^7\, kg$ initially at rest is pulled by a force of $5 \times 10^5\, N$ through a distance of $2 \,m$. Assuming that the resistance due to water is negligible, the speed of the ship is

• A. $2 \,ms^{-1}$
• B. $0.01\,ms^{-1}$
• C. $0.1\,ms^{-1}$
• D. $1 \,ms^{-1}$
• E. $5 \,ms^{-1}$

Answer 1

Answer: (D)

Given
$u=0 m =2 \times 10^{7}\, kg ; $
$F=5 \times 10^{5} ; S=2 m$
From work -energy theorem
$W=\frac{1}{2} m v^{2}-\frac{1}{2} m u^{2}=F S$
$\frac{1}{2} \times 2 \times 10^{-7} \times v^{2}=5 \times 10^{5} \times 2$
$10^{7} V^{2}=10^{6}$
$V^{2}=10^{-1}$
$V=\sqrt{10^{-1}}$