Question

Two bodies of masses 8 kg and 4 kg move along the x=axis in opposite directions with velocities of 11 m/s-positive x-direction and 7 m/s-negative x- direction, respectively. they collide and stick together. find their velocity just after collision

Answer 1

Momentum would remain conserved therefore

$\binom{p}{initial} = \binom{p}{final}$

p=momentum

$\binom{m}{1} \binom{u}{1} + \binom{m}{2} \binom{u}{2} = \binom{total \: mass}{final \: velocity}$

$\binom{m}{1} = 8kg \\ \binom{m}{2} = 4kg \\ \binom{u}{1} = 11i \\ \binom{u}{2} = - 7i \\ total \: mass \: = 8 + 4 = 12kg$

$8(11i) + 4( - 7i) = 12(v)$

$88i - 28i = 12v$

12v=60i

v=5m/s towards positive x direction

Answer 2

Answer:

Their velocity after collision is 5m/s towards positive direction.

Explanation:

Given that:

two bodies of mass,

m1= 8kg and m2= 4kg.

it moves along x axis that is in opposite.

velocity= 11m/s in positive direction and 7m/s in negative direction.

To find- velocity after their collision.

momentum would remain conserved that is

initial will be equal to final

m1+v1+m2+v2= total mass final velocity

8(11)+4(-7)=12

88-28=12

12v=60i

v=5m/s

Their velocity after collision is 5m/s towards positive direction.