Torque problem involving bicep holding ball

In summary, a human arm holding a heavy iron ball is described with a schematic diagram. The triceps and biceps muscles connect to the forearm at different distances from the elbow joint and can exert upward forces. The forearm and hand have a combined mass and center of mass, and the distance from the triceps to the ball is given. The question asks for the force exerted by the biceps when the triceps force is zero. The solution involves using the concept of torque and drawing a free body diagram, but the given equation includes inconsistent units and may be missing some necessary components. The individual asking for clarification expresses difficulty with solving torque problems and requests advice.
  • #1
elchoi
3
0

Homework Statement


A schematic diagram of the human arm is shown holding a
heavy iron ball (mass 5.0 kg). The triceps muscle connects to the
forearm 3.0 cm to the left of the elbow joint, while the biceps
muscle connects 5.0 cm to the right. Each of the muscles can
exert an upward force on the forearm when needed. The
forearm and hand together itself have a mass of 4.0 kg and a
center of mass 15 cm to the right of the elbow joint. The distance from the triceps
to the center of the ball is 35 cm

a. When the ball is being held as shown, the force exerted by
the triceps is approximately zero. What force must the
biceps be exerting?

Homework Equations


For this problem I attempted to use sigma torque equation to find how much force is needed for the bicep to hold the ball up.

The Attempt at a Solution


I found the forces drawing a free body diagram to be
force of bicep, force of ball, force of arm, and force of triceps.

so force of biceps = (5.0 x 9.8N) - (15 cm x 9.8N) - (3.0 x 9.8)
I feel like I am still missing a big chunk in my equation, but I seem to be having trouble with these torque problems any advice on how to solve them? =X
 
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  • #2
The quantities in the equation appear to have inconsistent units.

How is torque defined?
 

Related to Torque problem involving bicep holding ball

What is torque and why is it important in this scenario?

Torque is a measure of the force that causes an object to rotate around an axis. In the context of a bicep holding a ball, torque is important because it determines the ability of the bicep to maintain its position and keep the ball from falling. If the torque is too low, the bicep will not be able to hold the ball and it will drop.

How is torque calculated in this situation?

To calculate torque, you need to know the force applied and the distance from the axis of rotation. In this case, the force would be the weight of the ball and the distance would be the length of the bicep from the shoulder to the elbow. The formula for torque is T = F x d, where T is torque, F is force, and d is distance.

What factors can affect torque in this bicep and ball scenario?

The main factors that can affect torque in this scenario are the weight of the ball, the length of the bicep, and the angle at which the bicep is holding the ball. A greater weight or a shorter bicep will result in a higher torque, while a larger angle will decrease the torque.

How can the bicep increase its torque to hold the ball more securely?

The bicep can increase its torque by increasing the force it applies, either by contracting its muscle more or by holding the ball closer to the elbow. It can also decrease the distance from the axis of rotation by holding the ball closer to the shoulder. Additionally, changing the angle at which the bicep is holding the ball can also increase torque.

What other factors should be considered when analyzing this torque problem?

Other factors that should be considered include the strength and endurance of the bicep muscle, as well as the grip and stability of the hand holding the ball. In real-life scenarios, external factors like wind or slippery surfaces can also affect the torque needed to hold the ball in place.

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