Physics
posted by Bartholomew .
A 5 kg mass is thrown up with a velocity of 4 m/s from a height of 30 m onto a spring with a relaxed length of 10 m, and a constant of 400 N/m. What will the maximum compression of the spring be? What will the speed of the object be when the spring is compressed 0.3 m?

Have you tried applying conservation of energy? Show your work and one of us will gladly critique it.

(V2^2)=(Vi)^2+2ad
0=1619.6d
16=19.6d
d=0.816 m + 30 m = 30.816 meters above the ground
mgh = mgh + 1/2kx^2 = (5 kg)(9.8 m/s^2)(30.816) = 200x^249x+490
x=2.75 m
mgh=1/2kx^2+mgh+1/2mv^2
(5)(9.8)(30.186)=1/2(400)(0.3)^2+(5)(9.8)(9.7)+1/2(5v^2)
v=20.17 m/s