Grigoriy S. answered 12/06/21
AP Physics / Math Expert Teacher With 40 Years of Proven Success
Potential energy of the spring
U = 1/2 kx2,
here k =4.4 x 104 N/m - spring constant,
x - deformation of the spring.
To find the change in potential energy ΔU, you just need to subtract the values of 2 energies.
Remember that deformation should be converted to units - meters.
So, x1 =12.5 x 10-2 m and x2 = 15 x 10-2 m
Now we can write
ΔU = U2 - U1 = k/2 (x22 - x12)
Putting the values we will have
ΔU = 1/2·4.4 x 104 N/m ((15 x 10-2m)2 - (12.5 x 10-2 m)2)
Finally we get ΔU = 151 J