# Homework Help: Projectile Motion

1. Jan 14, 2010

### LampMan

1. The problem statement, all variables and given/known data

A prince trapped in a castle wraps a message around a rock and throws it from the top wall with an initial velocity of 12 m/s [42 deg above the horizontal] the rock lands just on the far side of the castles moat at a level 9.5m below the initial level. determine the rocks:
a) time of flight
b) width of moat
c) velocity of impact

2. Relevant equations

i dont know ive lost my formula sheet (but theyre basic ones) if i can just have my memory refreshed on what the equations are i can probably do it plus be able to continue on the rest of the unit exam review. my exam is next week and this question isnt for marks but for studying and i need help please

3. The attempt at a solution

dont know where to start

2. Jan 14, 2010

### payumooli

v = u + a*t
s = ut + 0.5*a*t^2
v^2 = u^2 + 2as

v - final velocity
u - initial velocity
s - distance traversed

use the two components of the initial velocity and proceed