Answer:
<h2>The current required winding is

</h2>
Explanation:
We can use the expression B=μ₀*n*I-------1 for the magnetic field that enters a coil and
n= N/L (number of turns per unit length)
Given data
The number of turns n= 1200 turns
length L= 0.42 m
magnetic field B= 1*10^-4 T
μ₀= 
Applying the equation B=μ₀*n*I
I= B/μ₀*n
I= B*L/μ₀*n


F=ma
F = 148×(85-35)÷20
F = 148×(50÷20)
F = 148×2.5
F = 370N
Most likely B. Will erode, if not it will grow weeds
gravitational force of earth is given by

so here the force will depend on the product of mass and gravity
so here force will be more if we took the condition of more masses
so here in 3rd figure
there will be maximum force of gravity on it
because it will have 6 boxes so there will be maximum mass
So figure of truck with 6 boxes on it is correct answer