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Toranc3
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Homework Statement
A painter (mass 61 kg) is walking along a trestle, consisting of a uniform plank (mass 20.0 kg, length 6.00 m) balanced on two sawhorses. Each sawhorse is placed 1.40 m from an end of the plank. A paint bucket (mass 4.0 kg, diameter 28 cm) is placed as close as possible to the right-hand edge of the plank while still having the whole bucket in contact with the plank.
(a) How close to the right-hand edge of the plank can the painter walk before tipping the plank and spilling the paint?
(b) How close to the left-hand edge can the same painter walk before causing the plank to tip?
(Hint: As the painter walks toward the right-hand edge of the plank and the plank starts to tip clockwise, consider the force acting upward on the plank from the left-hand sawhorse support.)
Homework Equations
Summation of forces
Summation of torques , tao=Fr
The Attempt at a Solution
Wp=weight of the plank, wg= weight of the guy, wb weight of the bucket, nr=normal of the right hand fulcrom
Wp=196N, Wg=588N, Wb=39.2N
Fy: -Wp-Wg-Wb+Nr
Nr=823.2 Newtons
Torque: N(1.6m)-Wg*x
x=2.24 meters.
I did my torque about the center of the plank. Wp
this is for part a. i am still working on part b and i will post it up in a bit. So basically in the torque you exclude the normal on the left hand fulcrum and the weight of the paint. is this right?
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