Question

A rain drop of mass (1/10) gram falls vertically at constant speed under the influence of the forces of gravity and viscous drag. In falling through 100 m, the work done by gravity is

• A. 0.98 J
• B. 0.098 J
• C. 9.8 J
• D. 98 J

Answer 1

The correct option is B 0.098 J

work done = mgh

m = mass of drop = 0.1 g = 0.00001kg

g =9.8m/s

h = 100m

work done = $0.00001\times 9.8\times 100$

= 0.098 J