Answer:
The average force exerted on the window due to two snowballs is 6 N
Step-by-step explanation:
Given:
Mass of snowballs
Kg
Velocity of snowball

For finding the average force,
Force is equal to the change in momentum,

Here, final velocity is zero so we write,

Where
sec

N
Above value of force is due to one ball, but here given in question there are two ball,

N
Therefore, the average force exerted on the window due to two snowballs is 6 N