MHB Find the average force required to hold the gun in position

AI Thread Summary
To find the average force required to hold a gun in position while firing, the impulse equation is applied, where force multiplied by time equals mass multiplied by change in velocity. Each bullet has a mass of 3 grams and a speed of 500 m/s, leading to a calculated momentum for one bullet, which is then multiplied by six for the total momentum of all bullets fired per second. Consistent unit conversion is crucial, either converting grams to kilograms for force in Newtons or speed to centimeters per second for force in dynes. Calculating impulse for one bullet over a shorter time frame yields the same force as for six bullets over one second. The discussion also includes a light-hearted side note about typing preferences on mobile devices.
Joe_1234
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A gun fires 6 bullets per second into a target. The mass of each bullet is 3g & the speed of 500 m/s. Find the average force required to hold the gun in position.
 
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Impulse equation ...

$F \cdot \Delta t = m \cdot \Delta v$
 
skeeter said:
Impulse equation ...

$F \cdot \Delta t = m \cdot \Delta v$
Tnx
 
You titled this "momentum" so it looks like you already knew the basic idea. The momentum of a single bullet is "mass times velocity" and you are given both of those. Of course, the momentum of 6 bullets is 6 times the momentum of a single bullet. Since this all happens in one second, divide by one second to get the force.

Be careful to use consistent units. You are given the mass in grams and the speed in m per second. Either convert mass to kg to get the force in Newtons or convert the speed to cm per second to get the force in dynes. I recommend the former.
 
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HallsofIvy said:
You titled this "momentum" so it looks like you already knew the basic idea. The momentum of a single bullet is "mass times velocity" and you are given both of those. Of course, the momentum of 6 bullets is 6 times the momentum of a single bullet. Since this all happens in one second, divide by one second to get the force.

calculating the impulse for one bullet over $\Delta t = \frac{1}{6} \text{ sec}$ yields the same result as six bullets in $\Delta t = 1 \text{ sec}$
 
Joe_1234 said:
Tnx
Serious question - is it harder to type “thanks” or “tnx “ on your phone? On mine the latter will auto correct to something else so it’s actually harder.
 
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