Question

A 15g bullet is fired from a gun of mass 3kg .if the speed of bullet just after firing is 300 ms-1 ,what is the recoil speed of gun

Answer 1

Mass of bullet=15×10^-3kg
mass of gun=3kg
recoil velocity=mass of bullet/mass of gun×velocity of bullet
=15×10^3/3 × 300
=15×10^-1
=1.5m/sec

Answer 2

$\Huge{\boxed{Solution:-}}}$

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Given :

Mass of bullet {m} = 15 gram = $\dfrac{15}{1000}\:kg$

Mass of Gun {M} = 3 kg.

Speed or velocity of bullet = 300 m/s.

To find :

Recoil velocity (speed) of

gun.

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Simple and short formula to

find recoil velocity is

$\Huge{\boxed{V=\dfrac{-mv}{M}}}$

where capital 'V' is recoil velocity

and small 'm' is mass of bullet and

capital 'M' is mass of gun and small

'v' is velocity of bullet.

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Let's find the recoil velocity

of gun by using that formula.

$\implies V=\dfrac{-mv}{M}\\\\\\\implies V=\dfrac{\dfrac{-15}{1000}\times300}{3}\\\\\\\implies V=\dfrac{-9}{6}\\\\\implies V=-1.5\:m/s$

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Therefore recoil velocity (speed) of

gun is -1.5 m/s