Question

A spring balance is adjusted at zero. Elastic collisions are brought about by dropping particles of one gram each on the pan of the balance. They recoil upwards without change is their velocities. If the height of fall of particles is 2 meter and the rate of particle dropping is 100 per seconds, then the reading of the balance is –

• A. 128 gm wt.
• B. 1252 gm wt.
• C. 625 gm wt.
• D. 1.25 gm wt.

Answer 1

Answer: (A)

128 gm wt.

Answer 2

W=2mvn,v=$\sqrt{2h}$