A 8-kg object with a velocity 5 m/s explodes into two fragments of equal mass.One flies off with a velocity of (3 -2 )m/s.The velocity of the other fragments is
A)7 + 2 m/s.
B)8 + 3 m/s.
C)47 - 2 m/s.
D)7 - 2

Question

A 8-kg object with a velocity 5  m/s explodes into two fragments of equal mass.One flies off with a velocity of (3  -2  )m/s.The velocity of the other fragments is
A)7 + 2 m/s. 
B)8 + 3 m/s. 
C)47 - 2 m/s. 
D)7 - 2

Quizplus · Accepted Answer

Conservation of momentum:
Initial momentum = Final momentum
mv = m1v1 + m2v2
Here, m1 = m2 = m/2 (mass of fragments)
v = 8 m/s (initial velocity)
m*(8) = (m/2)*(3-2) + (m/2)*(1+1)
8m = 2m
v1 + v2 = 8 m/s (initial velocity)
v1 = 3 m/s, v2 = 5 m/s
Using conservation of momentum, we get the velocity of the other fragment to be:
v2 - v1 = 5 - 3 = 2 m/s
The velocity of the other fragment is in the same direction as the first fragment. Therefore, the correct option is A) 7+2 m/s.

A 8-Kg Object with a Velocity 5 M/s Explodes