336,298 views
35 votes
35 votes
A .1 kg leaves the barrel of 5 kg gun with a speed of 400 m/s.  determine the recoil speed

User Randomblue
by
2.6k points

1 Answer

18 votes
18 votes

Answer:

8 m/s

Step-by-step explanation:

You want the recoil speed when a 0.1 kg slug leaves the barrel of a 5 kg gun at a speed of 400 m/s.

Momentum

The total momentum of the system remains constant before and after the slug leaves the barrel.

before: mv = 0 . . . . . all parts of the system are at rest

after: m1v1 +m2v2 = 0 ⇒ (0.1 kg)(400 m/s) +(5 kg)(s) = 0

40 kg·m/s + (5 kg)s = 0

s = (-40 kg·m/s)/(5 kg) = -8 m/s

The recoil speed of the gun is 8 m/s in the direction opposite to that of the slug.

User Kevin McMahon
by
3.2k points