Question

A bullet fired into a fixed target loses half of its velocity after penetrating 3cm. How much further it will penetrate before coming to rest assuming that it faces constant resistance to motion?
A. `1.0 cm`
B. `1.5 cm`
C. `2.0 cm`
D. `3.0 cm`

Answer 1

Correct Answer - A
Using law of conservation of total energy
Case `(i)` , `(1)/(2)m u^(2)=(1)/(2)m ((u)/(2))^(2)+Fxx3`
or `(3)/(4)((1)/(2)m u^(2))=Fxx3` …(i)
Case `(ii)` `(1)/(2)m u^(2)=FxxS` ....(ii)
or `(3)/(4)=(3)/(S)` or`S=4 cm`
`:.` Further distance travelled `=4-3=1cm`