- #1

Meowzers

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A boy carries a sack on one end of a very light stick that is balanced on his shoulder, at an angle of 22.0 degrees up from the horizontal. The mass of the sack is 7.00 kg, and it sits 1.20 m from his shoulder. If his hand is 0.350 m from his shoulder, on the other end of the stick, what is the magnitude of the downward force the boy exerts with his hand?

I drew somewhat of a force diagram, then:

Set x=force of hand

torque of hand + torque of wall = 0

rFcos(theta) + rFsin(theta) = 0

-(.350m)(x)(cos 22) + (1.2m)(9kg*9.8 m/s2)(sin 22) = 0

.3245x = 39.648

x = 122.18 N