Answer:
3.92 cm
Explanation:
k = spring constant of the spring scale = 1500 N/m
m = mass of the brick = 3 kg
x = stretch caused in the spring
h = height dropped by the brick = x
Using conservation of energy
Spring potential energy gained by the spring scale = Potential energy lost
(0.5) k x² = mgh
(0.5) k x² = mgx
(0.5) k x = mg
(0.5) (1500) x = (3) (9.8)
x = 0.0392 m
x = 3.92 cm
