Question

a bullet of mass 10g is if fired from a rifal with a speed of 36km calculate the speed of the recoil of the rifal if it mass is 5kg

Answer 1

Heya!
Here's Your Answer
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M1=10/1000kg
M2=5kg
V1=36×5/18
Therefore,
V1=10m/s
V2=?
Since Both Were Initially At Rest,
U1=0
U2=0
Now,
According To Law Of Conservation Of Momentum,
M1U1+M2U2=M1V1+M2V2
1/100×0+5×0=1/100×10+5×V2
0=1/10+5V2
-1/10=+5V2
-1/10÷5=V2
-1/50=V2
-0.02m/s=V2
Minus Sign Indicates gun is moving from right to left
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Hope This Helps..........!!!!!

Regards,
Surya

Answer 2

Hi friend
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Your answer
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Mass of a bullet = m1 = 10 grams = 0.01 kg

Initial velocity of the bullet = u1 = 0 m/s

Final velocity of the bullet = 36 km = v1 = 10 m/s

Mass of the rifle = m2 =5 kg

initial velocity of the rifle = u2 = 0 m/s

Recoil velocity of the rifle = v2 = ?

Now,
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By conservation of momentum,
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m1u1 + m2u2 = m1v1 + m2v2

=> (0.01 × 0) + (5 × 0) = (0.01 × 10) + (5 × v2)

=> 0 = 0.1 + 5v2

=> 5v2 = - 0.1

=> v2 = - 0.1/5

=> v2 = - 0.02 m/s

Here, '-' negative sign indicates that the recoil velocity is in the backward direction.

Therefore, recoil velocity of the gun = 0.02 m/s

HOPE IT HELPS