Question

A bullet is fired to a fided object after penetrating 3 cm its energy becomes half so how long it will travel so that final velocity becoms 0

Answer 1

Answer:Brainly.in

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Secondary SchoolPhysics 15+8 pts

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 resitance to motion?

Report by Somaal9419 16.05.2018

Answers

KunalVerma911

KunalVerma911 Expert

By the third equation of motion

v^2 = u^2+ 2as

Here let initial velocity u=x then after traveling 3 cm v=x/2 and s=3cm=0.03 m.

So

a = \frac{(v {}^{2} - u {}^{2} )}{2s} = \frac{ \frac{x {}^{2} }{4} - x {}^{2} }{2 \times 0.03}

= \frac{ - 3x {}^{2} }{4 \times 0.06} = - \frac{ - 3x {}^{2} }{0.24}

when the. bullet comes to rest final vel v=0

a = \frac{0 - x {}^{2} }{2s}

now equating the two values of a we get

\frac{ - 3x {}^{2} }{0.24} = \frac{ - x {}^{2} }{2s}

so s=0.04 m=4cm

Now distance moved when velocity changes from v/2 to 0 is

4cm-3cm=1cm Ans

PS Note that the acceleration expression is negative which means that the bullet is decelerating i.e. its speed is decreasing.

Answer 2

The bullet travel 6cm