Browse by Stream
QnA
Home
QnA
Go To Your Study Dashboard

Get Answers to all your Questions

header-bg qa
  • Home
  • Engineering
  • Answer please! A bullet fired into a fixed target loses half its velocity after penetratin 3 cm How much further it will penetrate before coming to rest assuming that it aces constant resistance to motion ?

A bullet fired into a fixed target loses half its velocity after penetratin 3 cm How much further it will penetrate before coming to rest assuming that it aces constant resistance to motion ?

  • Option 1)

    1.5 cm

  • Option 2)

    1.0 cm

  • Option 3)

    3.0 cm

  • Option 4)

    2.0 cm

 

Answers (1)

best_answer

As we learnt in

Law of Consevation of Momentum -

 \vec{F}=\frac{\vec{dp}}{dt}

\vec{F}=0            then \vec{p}=constant

\vec{p}=\vec{p}_{1}+\vec{p}_{2}+\cdots =const

- wherein

\ast Independent of frame of reference

 

 

 

For first part of penetration, by equation of motion,

\left ( \frac{u}{2} \right )^{2}= \left ( u^{2} \right )-2f\left ( 3 \right )

or\: \: \: \: \: \: \: 3u^{2}= 24f\cdots \cdots \cdots \left ( i \right )

For latter part of penetration,

0= \left ( \frac{u}{2} \right )^{2}-2fx

or \: \: \: \: \: u^{2}= 8fx\cdots \cdots \cdots \left ( ii \right )

From (i) and (ii)

3\times \left ( 8\: fx \right )= 24f

or \: \: \: \: x= 1 cm

Correct option is 2.

 


Option 1)

1.5 cm

This is an incorrect option.

Option 2)

1.0 cm

This is the correct option.

Option 3)

3.0 cm

This is an incorrect option.

Option 4)

2.0 cm

This is an incorrect option.

Posted by

prateek

View full answer

JEE Main high-scoring chapters and topics

Study 40% syllabus and score up to 100% marks in JEE

Similar Questions

Trending Articles/News

anam-khan

JoSAA 2024 round 4 seat allotment results out at josaa.nic.in; report online by July 15

Latest Question