If m1 accidentally falls off and shatters when it strikes the floor, the rod holding m4 will move to a vertical orientation so that m4 hangs directly below the end of the rod supporting m2. To what values should m2 and m3 be adjusted so that the other two rods will remain in equilibrium and be oriented horizontally

Ahuge (essentially infinite) horizontal nonconducting sheet 10.0 cm thick has charge uniformly spread over both faces. the upper face carries +95.0 nc/m2 while the lower face carries -25.0 nc/ m2. what is the magnitude of the electric field at a point within the sheet 2.00 cm below the upper face? (ε0 = 8.85 × 10-12 c2/n · m2)