QUICK ANSWER
The collision between two gas molecules or billiard balls can be approximated as elastic collisions. Elastic collisions are exchanges of kinetic energy between two bodies having different reference frames in which the total kinetic energy of the two bodies after collision is equal to the energy before collision.'
Explanation:
Given
Range of ball =7.88 m
Initial speed=13.1 m/s
and we know
Range of Projectile is






(b)other angle would be complementary of 

We can find the force by using the following formula;
N = ma + mg
Fa = ma = 76 x 1.2 = 91.2
Fg = mg = 76 x 9.8 = 744.8
N = 91.2 + 744.8 = 836
So, the force is 836 N.
Answer:
I learned this last year but I don't remember. Sorry