The desperate contestants on a TV survival show are very hungry. The only food t
ID: 2034360 • Letter: T
Question
The desperate contestants on a TV survival show are very hungry. The only food they can see is some fruit hanging on a branch high in a tree. Fortunately, they have a spring they can use to launch a rock. The spring constant is 1400 N/m, and they can compress the spring a maximum of 20 cm. All the rocks on the island seem to have a mass of 460 g.
(a) With what speed does the rock leave the spring?
___ m/s
(b) To what height can the rock be launched? (Assume the spring's equilibrium length is 50 cm.)
___ m
If the fruit hangs 15 m above the ground, will they feast or go hungry?
go hungry
feast
Explanation / Answer
a) Potential energy of the spring = Kinetic energy
0.5kx^2 = 0.5mv^2
1400*0.2^2 = 0.46*v^2
v = 11.03 m/s
b) 0.5mv^2 = mgh
0.5*11.03^2 = 9.8*h
h = 6.2 m
the feast will go hungry