A bullet moving with a velocity of 200 ,cm/s penetrates a wooden block and comes to rest after trave

English

Gujarati

Hindi

2.Motion in Straight Line

medium

A bullet moving with a velocity of $200 \,cm/s$ penetrates a wooden block and comes to rest after traversing $4 \,cm$ inside it. What velocity is needed for travelling distance of $9 \,cm$ in same block..........$cm/s$

A

$100$

B

$136.2$

C

$300$

D

$250$

Solution

(c) As ${v^2} = {u^2} – 2as \Rightarrow {u^2} = 2as$

$ \Rightarrow {u^2} \propto s$ ==> $\frac{{{u_2}}}{{{u_1}}} = {\left( {\frac{{{s_2}}}{{{s_1}}}} \right)^{1/2}}$

==> ${u_2} = {\left( {\frac{9}{4}} \right)^{1/2}}{u_1} = \frac{3}{2}{u_1} = 300cm/s$.

Standard 11

Physics

Share

Similar Questions

$v^2$ versus $s$-graph of a particle moving in a straight line is as shown in figure. From the graph some conclusions are drawn. State which statement is wrong?

medium

A body is moving with uniform acceleration describes $40\, m$ in the first $5 \,sec$ and $65\, m$ in next $5 \,sec$. Its initial velocity will be……..$m/s$

hard

A bullet fired into a fixed target loses half of its velocity after penetrating $3\, cm$. How much further it will penetrate before coming to rest assuming that it faces constant resistance to motion ?…….$cm$

normal

An object accelerates from rest to a velocity $27.5 \,m/s$ in $10 \,sec$ then find distance covered by object in next $10\, sec$……..$m$

medium

Speed of two identical cars are $u$ and $4u$ at a specific instant. The ratio of the respective distances in which the two cars are stopped from that instant is

easy

(AIEEE-2002)