A plank AB 3.0 m long weighing 20 kg and with its centre of gravity 2.0 m from the end A
carries a load of mass 10 kg at the end 4. It
rests on two supports at C and D as shown in
RA
B В
4
50 cm
50 cm
(1) Compute the values of the reaction
forces R; and R, at Cand D.
How far from D. and on which side of it,
must a mass of 24 kg be placed on the
plank so as to make the reactions equal?
What are their values?
(m) Without this 24 kg, what vertical force
applied at B will just lift the plank clear 30
of D? What is then the reaction at C?​

the order for strong to weak forces such as

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force

the fundamental forces are those forces that act between to objects or element to make interactions. there are four types of fundamental forces such as strong and weak nuclear forces (due to protons and electrons), electromagnetic force (due to the motion of electrons) and gravitational force (due to orbital movement of the planet). if these forces are arranged on the basis of their maximum strength then the order is

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force

i would say

0.93xc=0.93x3x10^8m/s

2.54cm is 1 inch

360seconds i 1 hr