Question

A dumb-bell of mass 10 kg falls from a height of 80 cm. How much linear momentum of the dumb-bell will transfer to the floor? $(g=10m/s^2)$

• A. 40 kg m/s
• B. 30 kg m/s
• C. 5 kg m/s
• D. 50 kg m/s

Answer 1

The correct option is A 40 kg m/s

We have,
Mass of the dumb-bell (m) = 10 kg
Height $\left(h\right)=80cm=\frac{80}{100}=0.8m$
Initial velocity u = 0
Acceleration = acceleration due to gravity = $g=10m/s^2$
Putting these values in the third equation of motion,
$v^2=u^2+2gh$
$v^2=0+2\times 10\times 0.8=16m^2/s^2$
v = 4 m/s
We know that linear momentum p = mv
= 10 × 4 = 40 kg m/s
40 kg m/s is transferred to the floor.