posted by dave on .
using the quadratic equation on a 2 dimensional projectile motion problem...
i am solving for tf and i have it worked all the way down to:
-100m(tf)-100m(tf) / -10m/s^2(tf)^2
-200m(tf) / -10m/s^2(tf)^2
is the answer 20 seconds? algebra is not my strong suit =(
What is the problem here. Is it something fired at some speed at some angle?
yes.. it's the "brothers of mercy" problem.
a plane is flying at 40 m/s, descending at an angle of 37 degrees to the horizontal. it is 100 m in the air and it is trying to drop a package to a man at R distance. what is R?
to find R, i needed to solve for time. that's where the quadratic came from
initial speed down = 40 sin 37
= 24.1 m/s
falls 100 meters, get speed down
v = 24.1 + 9.8 t
100 = 24.1 T + 4.9 T^2
4.9 T^2 + 24.1 T - 100 = 0
T = 2.68 s
now horizontal speed constant for 2.68 seconds
d = (40cos37)2.68
= 85.6 meters