Q3.23Multiple choice
It is a common observation that rain clouds can be at about a kilometre altitude above the ground.
- (a)If a rain drop falls from such a height freely under gravity, what will be its speed? Also calculate in km/h. (g = 10m/s2)
- (b)A typical rain drop is about 4mm diameter. Momentum is mass x speed in magnitude. Estimate its momentum when it hits ground.
- (c)Estimate the time required to flatten the drop.
- (d)Rate of change of momentum is force. Estimate how much force such a drop would exert on you. (e) Estimate the order of magnitude force on umbrella. Typical lateral separation between two rain drops is 5 cm. (Assume that umbrella is circular and has a diameter of 1m and cloth is not pierced through !!)