How much momentum will a dumb-bell of mass 10 kg transfer to the floor

1.	How much momentum will a dumb-bell of mass 10 kg transfer to the floor if it falls from a height of 80 cm? Take its downward acceleration to be 10 m/s2.
Answer» Mass of the dumbbell, m = 10 kg Distance covered by the dumbbell, s = 80 cm = 0.8 m Acceleration in the downward direction, a = 10 m/s² Initial velocity of the dumbbell, u = 0 Final velocity of the dumbbell (when it was about to hit the floor) = v According to the third equation of motion: v² = u² + 2as v² = 0 + 2 (10) 0.8 v = 4 m/s Hence, the momentum with which the dumbbell hits the floor is = mv = 10 × 4 = 40 kg m s⁻¹

How much momentum will a dumb-bell of mass 10 kg transfer to the floor if it falls from a height of 80 cm? Take its downward acceleration to be 10 m/s2.

Answer»

Mass of the dumbbell, m = 10 kg

Distance covered by the dumbbell, s = 80 cm = 0.8 m

Acceleration in the downward direction, a = 10 m/s²

Initial velocity of the dumbbell, u = 0

Final velocity of the dumbbell (when it was about to hit the floor) = v

According to the third equation of motion:

v² = u² + 2as

v² = 0 + 2 (10) 0.8

v = 4 m/s

Hence, the momentum with which the dumbbell hits the floor is

= mv = 10 × 4 = 40 kg m s⁻¹