Two objects of masses 100 g and 200 g are moving along the same line and direction with velocities of 2 m s-1 and m s-1 respectively. They collide and after the collision, the first object moves at a velocity of 1.67 ms-1. Determine the velocity of second object.
∴ Initial momentum of A = 100g x 2 ms-1
= 200 g ms-1
Initial momentum of B = 200g x 1 ms-1
= 200 g ms-1
∴ Total momentum of A and B before collision
= (200 + 200)g ms-1 = 400 g ms-1
Let the velocity of B after collision = v
∴ Momentum of B after collision = 200 g x v
Also, momentum of A after collision
= 100 g x 1.67ms-1 = 167 g ms-1
∴ Total momentum of A and B after collision
= 200g x v + 167 g ms-1
Now, by the law of conservation of momentum,
Momentum of A and B after collision
= Momentum of A and B before collision
200 g x v + 167g ms-1 = 400 g ms-1
200 g x v = (400 - 167) g ms-1
v = \(\frac{233}{200}\)ms-1 = 1.165 ms-1