How Does the Boy Balance the Forces While Carrying the Sack?

[lacar213]

Homework Statement

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?

Homework Equations

net torque = 0

The Attempt at a Solution

7.00 * 1.20 / .350 = 24 N

 

[LowlyPion]

Homework Statement

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?

Homework Equations

net torque = 0

The Attempt at a Solution

7.00 * 1.20 / .350 = 24 N

And you got from kg to N how?