Two objects of masses 100 g and 200 g are moving along the same line and direction with velocities of 2 ms-1 and 1 ms-1, respectively. They collide and after the collision, the first object moves at a velocity of 1.67 m s-1. Determine the velocity of the second object.
For this, firstly we have to calculate the total momentum of both the objects:
Momentum of first object:
= Mass of first object × Velocity of first object
= kg × 2 m/s
= 0.1 kg × 2 m/s
= 0.2 kg m/s
Momentum of second object:
= Mass of second object × velocity of object
= kg × 1 m/s
= 0.2 kg × 1 m/s
= 0.2 kg m/s
Total momentum = Momentum of first object + Momentum of second object
= 0.2 + 0.2
= 0.4 kg m/s
It is given that after the collision, the velocity of first object becomes 1.67 m/s
Momentum after collision (First object):
= kg × 1.67 m/s
= 0.1 kg × 1.67 m/s
= 0.167 kg m/s
Let, the velocity of second object after the collision be v m/s
Momentum after collision (Second object)
= kg × v m/s
= 0.2 kg × v m/s
= 0.2v kg m/s(ii)
Total momentum of the objects after collision = 0.167 + 0.2 v
We know that,
According to the law of conversion of momentum:
Total momentum before collision = Total momentum after collision
0.4 = 0.167 + 0.2 v
0.2 v = 0.4 – 0.167
0.2 v = 0.233
v =
v = 1.165 m/s
Therefore, the velocity of second object will be 1.165 m/s