The Student Room Group
Reply 1
help!
Reply 2
Find Moment=forcexdistance (perpendicular distance from pivot)

first force is the 30N, moment due to this force:30x 20= 600 Ncm

second force would be the one exerted by the piston, the moment due to this should also be 600Ncm,we know the distance from pivot, but we dont know the force, so u have:

moment=forcexdistance
600=fx 4

so force is 600/4 = 150 N