# Homework Help: Golf ball, projectile question

1. Apr 12, 2012

### bobmarly12345

1. The problem statement, all variables and given/known data
a golf ball is struck at an angle of 30 degree with respect to the horizontal, at a velocity of 11m/sec. the golf course is perfectly level and the golf ball stops instantaneously when it hits the ground.
a) determine the horizontal distance travelled by the golf ball
b) determine the maximum height attained by the golf ball
c) if the golf ball is to travel a distance of 100m using the same initial trajectory, determine the required initial velocity

2. Relevant equations
(u²sin2theta)/g
(u²sin²theta)/2g
sqrt((rg)/sin2theta)

3. The attempt at a solution
vertical component = 11sin30
horizontal " = 11cos30

a) range = [11²xsin(2x30)]/9.81 = 10.9m
b) height = [(11²xsin(30)²)/2x9.81 = 1.54m
c) 100m/s
sqrt((100.9.81)/sin(2x30))=33.7m/s

thats what i've done, i think its right but would like it if someone could check if i'm doing it right? whoever is hitting this golf ball doesnt seem very good if they're hitting it 10.9m :)
cheers

2. Apr 12, 2012