Respuesta :
Answer:
21.52 cm
Explanation:
Given that
mass of the spring, m = 3.15 kg
Length of the spring l2, = 13.4 cm = 0.134 m
Length of the spring l1 = 12 cm = 0.12 m
change in extension, x = 0.134 - 0.12 = 0.014 m
Acceleration due to gravity, g = 9.8 m/s²
Potential Energy, U = 10 J
See attachment for calculation

Answer:
Final Length = 12.45 cm
Explanation:
First we need to find the spring constant. From Hooke's Law:
F = kΔx
where,
F = Force Applied on Spring = Weight = mg = (3.15 kg)(9.8 m/s²) = 30.87 N
k = spring constant = ?
Δx = change in length of spring = 13.4 cm - 12 cm = 1.4 cm = 0.014 m
Therefore,
30.87 N = k(0.014 m)
k = (30.87 N)/(0.014 m)
k = 2205 N/m
Now, for the Potential Energy of 10 J:
P.E = (1/2)KΔx²
where,
P.E = Potential Energy of Spring = 10 J
Δx = ?
Therefore,
10 J = (2205 N/m)Δx²
Δx = √[10 J/(2205 N/m)
Δx = Final Length - Initial length = 0.0045 m = 0.45 cm
Final Length = 0.45 cm + 12 cm
Final Length = 12.45 cm