This question is incomplete, the complete question is;
For this force system the equivalent system at P is ___________
A) FRP = 40 lb (along +x-dir.) and MRP = +60 ft.lb
B) FRP = 0 lb and MRP = +30 ft.lb
C) FRP 30 lb (along +y-dir.) and MRP = -30 ft.lb
D) FRP 40 lb (along +x-dir.) and MRP = +30 ft.lb
Answer:
D) FRP 40 lb (along +x-dir.) and MRP = +30 ft.lb
Explanation:
From the figure in the image i uploaded along this answer;
FRP = ( 40 lb i + 30 lb j ) + [30 lb (-j)]
Where i and j are the unit vectors along X & Y axis respectively.
So, FRP = 40 lb i
that is, FRP = 40 lb along +X direction
MRP = [ 30 lb x ( 1 ' + 1' ) ] +( -30 lb x 1 ' )
= (30 lb x 2 ' )- 30 lb ft
= 60 lb ft - 30 lb ft
= 30 lb ft
Therefore option(D) is correct
