Torque & Equilibrium Video Lessons

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Problem: A woman weighing 670 N does a pushup from her knees, as shown in the figure. (Figure 1) Part A What are the normal forces of the floor on each of her hands? Express your answer to two significant figures and include the appropriate units. Part B What are the normal forces of the floor on each of her knees? Express your answer to two significant figures and include the appropriate units.

FREE Expert Solution

Under equilibrium, net torque is zero:

Στ=0

Similarly, the net force is zero:

ΣF=0

Part A

The net torque about the legs of the woman is zero.

Therefore:

Στ=w(54×10-2)-FN(76×10-2)=0FN(76×10-2)=w(54×10-2)FN=(670)(54×10-2)(76×10-2)

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Problem Details

A woman weighing 670 N does a pushup from her knees, as shown in the figure. (Figure 1) 


Part A What are the normal forces of the floor on each of her hands? Express your answer to two significant figures and include the appropriate units. 

Part B What are the normal forces of the floor on each of her knees? Express your answer to two significant figures and include the appropriate units.

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