Zero, cause the positive and negative work cancel out :)
what about it do you need to know love?
The inductance of a solenoid is given by:

where

is the vacuum permeability
N is the number of turns of the solenoid
A is the area of one loop of the solenoid
l is its length
For the solenoid in our problem, N=500, and the radius of one loop is r=0.025 m, so the area of one loop is

and its length is l=0.20 m
So the inductance of the solenoid is
use F = ma
F : force m : mass a : acceleration
so
f = 5kg * 20 m/s2 = 100 N
Answer:
The distance of m2 from the ceiling is L1 +L2 + m1g/k1 + m2g/k1 + m2g/k2.
See attachment below for full solution
Explanation:
This is so because the the attached mass m1 on the spring causes the first spring to stretch by a distance of m1g/k1 (hookes law). This plus the equilibrium lengtb of the spring gives the position of the mass m1 from the ceiling. The second mass mass m2 causes both springs 1 and 2 to stretch by an amout proportional to its weight just like above. The respective stretchings are m2g/k1 for spring 1 and m2g/k2 for spring 2. These plus the position of m1 and the equilibrium length of spring 2 L2 gives the distance of L2 from the ceiling.