A pellet (20g) is launched horizontally off a cliff (20m high) from a spring-loaded gun. The spring has constant k= 1800 N/m and is compressed 0.10m before launch.
How much energy is stored in the spring before launch?
If all that energy is transferred to the pellet, how fast is it moving just after launch?
How much kinetic energy does the pellet have just before it hits the ground?
How fast will the pellet be going before it hits the ground?
a) EPE = 1/2 k x^2 = 1/2 1800 .1^2
b) EPE (you just found) = 1/2 m v^2 (be sure mass is in kg)
c) KE1 you just found (same as a), KE2 comes from converted GPE = mgh = .02(9.8)20. Total KE = KE1 + KE2
d) Total KE = 1/2mv^2, solve for v