Question

The mass of ship is $2 \times 10^{7} kg$. On applying a fore of $25 \times 10^{5} N$, it is displaced through $25\, m$. After the displacement. The speed aquired by the ship will be :

• A. 12.5 m/s
• B. 5 m/s
• C. 3.7 m/s
• D. 2.5 m/s

Answer 1

Answer: (D)

Here : Mass of ship $m=2 \times 10^{7} kg$
Force $F=25 \times 10^{5} N$
Displacement $s=25\, m$
According to the Newton's second law of motion
$F =m a$
or $a=\frac{F}{m}=\frac{25 \times 10^{5}}{2 \times 10^{7}}$
$=12.5 \times 10^{-2} m / s ^{2}$
The relation for final velocity is
$v^{2} =u^{2}+2 as$
or $v^{2} =0 +2 \times\left(12.5 \times 10^{-2}\right) \times 25$
or $v =\sqrt{6.25}=2.5\, m / s$