qz7sol_3081sp10 - Monday March 22nd 2010 TA Tomoyuki...

TA: Tomoyuki Nakayama Monday, March 22 nd , 2010
PHY 2048: Physic 1, Discussion Section 3081
Quiz 7 (Homework Set # 10)
Name: UFID:
Formula sheets are not allowed. Calculators are allowed. Do not store equations in your calculator.
You need to show all of your work for full credit.
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In the figure below right, horizontal scaffold 2, with uniform mass m
2
= 20.0 kg and length L
2
= 2.00
m, hangs from horizontal scaffold 1, with uniform mass m
1
= 40.0 kg. A 30.0 kg box of nails lies on
scaffold 2, centered at distance d = 0.500 m from the left end.
a) Draw all the forces exerted on the lower scaffold in the figure,
and write down the translational equilibrium condition (balance
of forces equation) and rotational equilibrium condition (balance
of torques equation) for the lower scaffold.
Four forces are exerted on the lower scaffold, the gravitational
force exerted at the center of the scaffold, two tension forces
exerted at the both ends and the force from the box, whose magnitude is equal to the gravitational