Question

Two masses of 0.25 kg each moves toward each other with speed 3m/s and 1m/s collide and stick together. Find the final velocity.

Answer 1

Momentum of 1st mass before Collison

0.25 × 3
= 0.75 kg-m/s

Momentum of second object before Collison

0.25 × 1 kg-m/s

Total momentum = 0.75 + 0.25 = 1 kg -m/s


After Collison they stick together, so their mass become

0.25 + 0.25 = 0.5

We know that,
Momentum before Collison = Momentum after Collison

Momentum before Collison = 1kg-m/s

=> Momentum after Collison = 1 kg m/s

After Collison mass = 0.5kg
let Velocity = v

Hence after Collison,
Momentum = 1

=> mass × velocity = 1

=> 0.5 × v = 1

=> v = 1/0.5

=> v = 2m/s

Hence velocity after Collison = 2m/s

Hope it helps dear friend ☺️✌️✌️

Answer 2

Momentum of 1st mass before Collison
0.25 × 3
= 0.75 kg-m/s
Momentum of second object before Collison
0.25 × 1 kg-m/s
Total momentum = 0.75 + 0.25 = 1 kg -m/s
After Collison they stick together, so their mass become
0.25 + 0.25 = 0.5
We know that,
Momentum before Collison = Momentum after Collison
Momentum before Collison = 1kg-m/s
Momentum after Collison = 1 kg m/s
After Collison mass = 0.5kg
let Velocity = v
Hence after Collison,
Momentum = 1
mass × velocity = 1
0.5 × v = 1
v = 1/0.5
v = 2m/s

Hence velocity after Collison = 2m/s