A)Detemine the horizontal force (F) required to move the plate across the factory floor.? b) Determine the mass of the plate?

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1 Answer
Mar 21, 2018

See below.

Explanation:

Assuming

1) A coordinate system with origin at the force vec FF application point
2) Brass plate with unknown mass distribution.

Calling

vec F_A = 3.5(cos 40^@, sin 40^@)FA=3.5(cos40,sin40)
vec F_B = 2.8(-cos 50^@, sin 50^@)FB=2.8(cos50,sin50)
vec F_G = m g (0,-1)FG=mg(0,1)
vec F = f(-1,0)F=f(1,0)

O = (0,0)O=(0,0)
A = (0,1)A=(0,1)
B = (2.5,1)B=(2.5,1)
G =(x_G,y_G)G=(xG,yG) Brass plate mass center

we have

Null force resultant

vec F_A+vec F_B+vec F_G+ vec F = vec 0FA+FB+FG+F=0

Null resulting moment regarding point OO

vec F_A xx (A-O)+vec F_B xx( B - O) + vec F_G xx (G-O) = vec 0FA×(AO)+FB×(BO)+FG×(GO)=0

or equivalently

{(3.5cos 40^@-2.8 cos50^@=f), (3.5sin 40^@+2.8sin 50^@= m g), (3.5 cos 40^@-2.8 cos 50^@-2.5 xx 2.8 sin 50^@+x_G m g = 0):}

Solving for f,m,x_G we obtain

f = 0.88 N
m = 4.39/g
x_G = 1.02