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 ms−1. Determine the velocity of the second object.
Mass of one of the objects, m1 = 100 g = 0.1 kg
Mass of the other object, m2 = 200 g = 0.2 kg
Velocity of m1 before collision, v1=2ms−1
Velocity of m2 before collision, v1=1ms−1
Velocity of m1 after collision, v3=1.67ms−1
Velocity of m2 after collision = v4
According to the law of conservation of momentum:
Total momentum before collision = Total momentum after collision
∴m1v1+m2v2=m1v3+m2v4
0.1(2)+0.2(1)=0.1(1.67)+0.2(v4)
0.4=0.167+0.2v4
v4=1.165ms−1
Hence, the velocity of the second object becomes 1.165 m/s after the collision.