# Projectile motion question (1 Viewer)

#### Exp

##### Member
Hey! Could you guys help me with this problem? You don't have to answer all of the parts, just help me get started
A ball is thrown horizontally from the top of a cliff and hits the ground 6 seconds later at 30 degrees to the vertical, moving at 67.9 m/s. Find:
a) the initial velocity of the projectile
b) initial horizontal and vertical velocity
c) range
e) final horizontal and vertical velocity

#### Sp3ctre

##### Active Member
Some prep work I did before answering the questions:
Uy = 0

Vy = 67.9 cos 30
= 58.80... m/s
Vx = 67.9 sin 30
= 33.95 m/s

a) Uy = 0 (launched horizontally)
Ux = Vx
= 33.95 m/s

Therefore initial velocity = 33.95 m/s horizontally (at 0 degrees to the horizontal)

b) Initial horizontal velocity = 33.95 m/s
Initial vertical velocity = 0 m/s

c) Range = Ux*t
= 33.95 * 6
= 203.7 m

e) All worked out already in prep work again:
Final horizontal velocity = 33.95 m/s
Final vertical velocity = 58.80... m/s (to 2 d.p)

Hope that all makes sense. I am very prone to making careless mistakes too so let me know if one or more of my answers do not match your answers.

#### Exp

##### Member
Yep, your answers are spot on! Thank you so much for the help