Respuesta :
Answer:
C) 388.07
Explanation:
It is a spring therefore, there must be Elastic potential energy. Now what is the formula for elastic potential energy? It is 1/2 *k *x^2
K=spring constant
x= displacement Â
1/2=.5 (hate fractions)
Now, Displacement simply means (how much was it moved?) So, that means subtract.
87-20= 67 Â x=67
Next, do x^2 (so you don't make a mistake by squaring everything :) Â )
67*67=4,489
NOW, do....
.5*1729*4,489=3,880,740.5
Now convert to Joules, I just did 3,880,740.5 Â / 10^3 = 3880.745
round to 3880.7 J Â
                                ~There you go loves !