Question

A spacecraft of mass 100 kg breaks into two when its velocity is ${10}^{4}m{s}^{-1}$. After the break, a mass of 10 kg of the spacecraft is Left stationary. The velocity of the remaining part is

• A. ${10}^{3}m{s}^{-1}$
• B. $11.11\times {10}^{3}m{s}^{-1}$
• C. $11.11\times {10}^{2}m{s}^{-1}$
• D. ${10}^{4}m{s}^{-1}$
• E. $1100m{s}^{-1}$

Answer 1

Answer: (B)

$11.11\times {10}^{3}m{s}^{-1}$

Given, $m=100kg,m_2=10kg$ and $u={10}^{4}m{s}^{-1}$
From conservation of momentum,
$m.u=m_1{v}_1+m_2{v}_2$
$100\times {10}^4=10\times 0+90\times v_2$
$100\times {10}^4=0+90\times v_2$
$v_2=\frac{100\times {10}^4}{90}$
$v_2=1.1\times {10}^4$
$v_2=11.11\times {10}^{3}m{s}^{-1}$