Question

Two bodies of masses 0.1 kg and 0.4 kg move towards each other with the velocities 1 m/s and 0.1 m/s respectively. After collision they stick together. In 10 sec the combined mass travels

• A. 120 m
• B. 0.12 m
• C. 12 m
• D. 1.2 m

Answer 1

The correct option is D 1.2 m

According to conservation of momentum
$m_1{v}_1+m_2{v}_2=(m_1+m_2)v,$
where v is common velocity of the two
bodies
$m_1=0.1kg,m_2=0.4kg$
$v_1=1m/s,v_2=-0.1m/s$
$\therefore 0.1\times 1+0.4\times (-0.1)=(0.1+0.4)v$
or, $0.1-0.04=0.5v$
$v=\frac{0.06}{0.5}=0.12m/s$
Hence, distance covered $=0.12\times 10=1.2m$