Question

Please Help!!

A bullet of mass 5 grams is fired with a velocity of 350 m/s from a 4 kg gun. Calculate:

a) the recoil velocity of the gun

b) the force on the bullet if the expanding gases act on the bullet for .006 s


I already figured out the recoil velocity which is .0437 m/s

thanks!

Answer 1

oh ok so the expanding gases will keep acting on the bullet until it stops?

Answer 2

a = .437/.006 = 72.833 m/s^2 ?

Answer 3

F= .005 * -72.83 = -.3641 N why does it seem so little

Answer 4

oh lol yeah me too..

Answer 5

So the acceleration is -7.28 m/s^2

Answer 6

F= .005 * -7.28 = -.0364 ?

Answer 7

should I be using the bullets velocity instead of the recoil? :S so confused

Answer 8

yeah i did convert to kg

Answer 9

Ok I just did this whole problem wrong, I'm so sorry. I didn't realize that the bullet's velocity was given.

Answer 10

Okay so force equals mass x acceleration.

We have the mass of the bullet, 5g.

However, we do not have the acceleration.

Can we find the acceleration? Yes, we can.

The formula for acceleration is vf-vi/t

vf=final velocity
vi= initial velocity.

Velocity is displacement over time. You have the final velocity of the bullet given, which is 350 m/s, before the bullet was fired, it had not been displaced, so the velocity was 0 m/s.

The time is a given. It is 0.006 seconds.

Now we will plug the numbers into the equation.

Answer 11

a=58333 m/s^2

Answer 12

350m/s / .006s = 58333 m/s^2

Answer 13

it can't be smaller than 350 - the denominator is less than zero

Answer 14

~less than 1

Answer 15

My calculator is giving me the wrong answer

Answer 16

blasted technology!! ^_^

Answer 17

A = VF-VI/T
A= 350m/s-0m/s/0.006s
A=350/0.006
A=58333m/s2

Force = mxa

Force = 0.005(convert the 5g to kg)*58333
Force = 291.67 N

Answer 18

okay thanks guys :)))