Concept explainers
(a)
The force which is greater and the reason for the two forces to be different.
Answer to Problem 11TP
The force on bicep is
Explanation of Solution
Given:
The weight of the dumbbell is
Formula used:
The relation between the mass and weight of forearm is,
The relation between the force and the weight of the bicep using the second condition of equilibrium in which the net torque is zero is,
The free body diagram for the hand is shown below.
Figure-(1)
From the above figure, all the three forces are acting perpendicular at the pivot.
Let mass of the forearm be
Calculation:
The weight of the forearm is calculated as,
The force on the bicep is calculated as,
Solve further,
The force on dumbbell is calculated as,
Compare the force of the dumbbell with the force on the bicep.
Conclusion:
Thus, the force on bicep is
(b)
Whether the force on the bicep muscles changes or if it remains the same if the weight is curled towards the body.
Answer to Problem 11TP
The force on bicep is
Explanation of Solution
Given:
The bicep makes an angle of
Formula used:
The relation between the force and weight of the bicep is,
Torque is generated by the weight of the forearm and the weight of the dumbbell.
Calculation:
The force on the bicep is calculated as,
Solve further,
Conclusion:
Thus, the force on the bicep is
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Chapter 9 Solutions
College Physics
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