Question

A body of mass 1000 kg is moving horizontally with a velocity of 6 m/s. If 200 kg extra mass is added, the final velocity (in m/s) is:

• A. 5 m/s
• B. 4 m/s
• C. 2 m/s
• D. 6 m/s

Answer 1

Answer: (A)

5 m/s

Answer 2

Since there are no external forces, momentum is conserved. Initially:

$\text{Initial momentum} = 1000 \times 6 = 6000 \, \text{kg m/s}$

After adding 200 kg of mass, the total mass becomes 1200 kg. Let the final velocity be $v$.

Using conservation of momentum:

$1200 \times v = 6000$ $v = \frac{6000}{1200} = 5 \, \text{m/s}$