EXPERT Physical Science question?

Question

Please state answer and explain:

What is the recoil velocity of a 0.75 kg gun when the bullet it fires has a mass of 10 g and a velocity of 500 m/sec?

A. 6666.7 m/sec
B. 37.5 m/sec
C. 37500 m/sec
D. 6.7 m/sec

Thank-you, you are a genius.....(IF YOU ARE CORRECT!)

Answer 1

10g = 0.01kg. Linear momentum is conserved after bullet has been fired. Let m1=mass of gun, m2 = mass of bullet, v1= final velocity of gun, v2 = final velocity of bullet:

p(before) = p(after). The gun and bullet are initially at rest so p(before) = 0, so

p(after) = o
(m1)(v1) + (m2)(v2) = 0. We want to find v1, solve:

v1 = -(m2)(v2)/(m1)
We can ignore the negative sign as they actually want speed (and not velocity as stated), so substituting values:

v1 = 0.01x500/0.75
v1 = 6.7m/s

Answer 2

OK, its been a long time since I have consider this kind of problem, but ... it seems like a common sense ratio. Clearly, the gun's recoil velocity is going to be far less than the forward velocity of the projectile itself; thus, 10 g at 500 m/sec, with 750 g gun mass at Rv velocity. Rv = [(10 g X 500 m/sec.) / 750 g] = 6.7 m/sec.

Answer 3

Start with:

Force = Mass x Velocity

So, the force of the bullet is 10g x 500m/sec = 5000 g*m/sec

The force on the gun is the same as the force on the bullet, but now you're solving for the velocity of the gun:

5000 g*m/sec = 750g x V

5000 g*m/sec / 750 g= V

6.7 m/sec = V (answer is D)

Answer 4

You need to use conservation of linear momentum. Linear momentum is equal to mass times velocity. The linear momentum of the bullet must equal the linear momentum of the gun.

mv = MV where m is mass of bullet, M is mass of gun, v is velocity of bullet, and V is velocity of gun.

mv/M = V

so (0.010 kg * 500m/s) / 0.750 kg = 6.7 m/s so D is correct.

***FYI***

Force is NOT m*v, it is m*a by Newton's Second Law. It is much easier to use momentum instead of force to find the final velocity of the gun in this problem.

Answer 5

Conservation of momentum:
MV = MV (mass of the gun x velocity of the gun) = (mass of the bullet x velocity of the bullet)
(.75 kg) v = .01 kg (500 m/s)
.75 kg (v) = 5 kg-m/s
v = 6.7 m/s
(d)

Answer 6

Wow.... I am sure some is going to give you answer, b/c it is simple. Me being me... use the conservation of momentum and remember before the gun was fired the masses are together and it's velocity is zero.

Answer 7

i've got self belief it is a chemical replace as a results of fact at first the two soltions have been colorless yet whilst mixed at the same time they brought about a chemical reaction which made them turn white. Alsoa powder shaped on the backside which shows some form of ionic bonding befell and probable made a salt