Projectile Motion- Need help with equations to use for a falling object

[Cav101]

Homework Statement

A trebuchet misfires and its 450kg projectile falls from the sling at the vertical height of the firing arm,

1) What force will the projectile hit the ground?

2) If the trebuchet is 5.40m tall with the firing arm in the vertical position, how long will the projectile take to fall to the ground?

3) If the trebuchet is reloaded and fired again, with a misfire occurring with the sling fully above the firing arm. If it takes 1.21s to hit the ground, what is the extra length of the sling line?

m=450kg
g=9.8
height=5.40m
time (Q3) 1.21s

Homework Equations

I'm not sure of the equations to use, that's why I'm asking. I can do the questions once I know how to use the equation

The Attempt at a Solution

1) F=ma= 450x9.8=4410N ?
2&3 I don't know how to do

 

[Paulie323]

from what i see you did number 1) correct but to do numbers 2) and 3) you must use the kinematics equations

2) solve for time when:
t=?
x=0m
x(initial)=5.40m
v(initial)=0
a=-9.8m/s^2

 

[jmb88korean]

Paulie323 is correct. Plug his numbers into x(final)= x(initial) + v(initial)t + (1/2)(-9.8)t^2. Use quadratic. Simply plug in for t instead of x for 3.