20 raindrops fall on an umbrella. The following day, 10 hail stones fall on the umbrella. All drops of rain and hail are of equal mass m and are traveling at the same velocity v. Both of these (rain and hail) fall on the umbrella in 1 second. What can we say about the Force exerted on the umbrella to hold it up

the force exerted by the umbrella against the drops is the same in both cases  

Explanation:

In this exercise the total mass of the raindrops and the hail are equal, therefore the momentum that these drops create is

raindrops       I₁ = ∫ F dt

hail                 I₂ = ∫ F dt

since the mass and the velocity is the same the force is the weight of the drops

                  F = mg

whereby the impulse is

                 I₁ = mg t

                 I₂ = mg t

we can see that the impulses generated by hail and raindrops are equal, therefore the force exerted by the umbrella against the drops is the same in both cases