Question

The hero of a stunt film fires 50 g bullets from a machine gun, each at a speed of 1.0 km/s. If he fires 20 bullets in 4 seconds, what average force does he exert against the machine gun during this period ?​

Answer 1

Given:

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• Hero of a stunt film fires 50 g bullets from a machine gun and each at a speed of 1.0 km/s.

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To find:

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Average force exerted against the machine gun during this period if he fires 20 bullets in 4 seconds.

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Solution:

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We know that,

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p = mv

where, p is momentum

m is mass

and v is velocity.

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So, by substituting the known values here,

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Momentum of each bullet = 50 g × 1.0 km/s

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= 0.05 kg × 1000 m/s

= 50 kgm/s

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Momentum of each bullet 50 kgm/s. It means the gun is imparted 50 kgm/s by each time time bullet was fired.

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Now, the rate of change of momentum of the gun

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$= \frac{50 \: kgm/s \: \times 20 }{4 \: s} \\ \\ = 250 \: N$

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Hence, the average force that the hero exert against the Machine during this period is 250 N.

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• p = mv (where p is momentum, m is mass and v is velocity).

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An object's momentum is the product of its velocity and mass. The quantity describes, for instance, the impact that a moving vehicle has on an object that it hits or the penetrative power of a speeding bullet. When the object travels at a constant speed, it neither gains nor loses momentum. When two objects collide, they again together gain and lose no momentum. The only way for a body to gain momentum is for an external force to act on it.

Answer 2

Question :-

The hero of a stunt film fires 50 g bullets from a machine gun, each at a speed of 1.0 km/s. If he fires 20 bullets in 4 seconds, what average force does he exert against the machine gun during this period ?

Answer :-

$\red{\bigstar}$ Force[F]

$\huge\leadsto{\sf\purple{250 \: N}}$

Given:

Mass = 50 kg

Speed = 1.0 km/s.

Have to find :-

What's the average force exerted against the machine gun during this period if he fires 20 bullets in 4 seconds ?

Solution:

Let's find out the momentum first :-

Applying formula :-

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p = mv

" p " = momentum

" m " = mass

" v " = velocity

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As according to this :-

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Momentum = 50 g × 1.0 km/s

= 0.05 kg × 1000 m/s

= 50 kgm/s.

Then , Now the rate of change of momentum :-

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50 kgm/s × 20 /4s

= 250 N

$\therefore\underline{\boxed{\textsf{F = {\textbf{250N}}}}} \qquad\qquad \bigg\lgroup\bold{Average\ force} \bigg\rgroup$

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