Question

What will be the transfer of momentum when a dumb bell of mass 15 kg falls from a height of 50cm and does not rebound? ( Take its downward acceleration to be 10 ms^-2)

• A. 58 Ns
• B. 60 Ns
• C. 59 Ns
• D. 65 Ns

Answer 1

The correct option is A

58 Ns

Step 1: Calculate the final velocity of the dumb-bell

Mass of dumb–bell (m) = 15 kg

Initial velocity (u) = 0

Final velocity (v) = ?

Distance (S) = 50 cm = 0.5m

Acceleration (a) = 10 ms^–2

We know v² – u² = 2aS

v² – (0)² = 2 × 15 × 0.5

v² = 15

v = 3.87 ms^–1

Momentum of dumb-bell transferred to ground = mv = 15 × 3.87 = 58 Ns.