N Angular Kinetics: Calculating Force Needed to Maintain 45° Position

So I can't help you there.In summary, the forearm and hand are held at a 45 degree angle to the humerus and the centre of gravity is located 15cm from the joint centre at the elbow. The elbow flexor muscles attach at an average distance of 3cm from the joint centre. To maintain this position, a force of approximately 192.5N must be exerted by the forearm flexors.
  • #1
bionut
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A 35N hand and forearm are held at a 45 degree angle to the vertically oriented humerus. The centre of gravity of the forearm and hand is located at a distance of 15cm from the joint centre at the elbow, and the elbow flexor muscle attach at an average distance of 3cm from the joint centre. How much force must be exerted by the forearm flexors to maintain this position?

Okay this is my attempt at the question:

Wt= 35N
dwt=0.15m
df=0.03m

fm(sin45) x (0.03m) = (35N) X (0.15m)
fm (0.02) = 5.25
fm= 262.5

Rv= 262.5 sin 45 - 35N
Rv=185.62 - 35
Rv=150.62

Rh= 262.5 Cos 45
Rh= 185.62

R= SqRoot (185.62)sqr + (150.62)sqr
R=239.04 N

But my answer is wrong can anyone see where I went wrong? My answer should be 192.5
 
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  • #2
bionut said:
How much force must be exerted by the forearm flexors to maintain this position?

Okay this is my attempt at the question:

Wt= 35N
dwt=0.15m
df=0.03m

fm(sin45) x (0.03m) = (35N) X (0.15m)
I'd have said:
fm(cos45) x (0.03m) = (35N) X (0.15m) x cos45

I haven't figured out why you calculate R. The question doesn't seem to ask for it.
 

1. What is N Angular Kinetics?

N Angular Kinetics is a branch of physics that focuses on the motion and forces associated with objects moving in a circular path, such as a pendulum or a rotating wheel.

2. How is force calculated in N Angular Kinetics?

The force needed to maintain a 45° position in N Angular Kinetics is calculated using the formula F = m * a, where F represents the force, m is the mass of the object, and a is the angular acceleration.

3. Why is a 45° position significant in N Angular Kinetics?

A 45° position is significant because it represents the maximum force needed to maintain a circular motion. Any angle greater or less than 45° would require a greater or lesser force, respectively.

4. How does N Angular Kinetics relate to real-world applications?

N Angular Kinetics is used in various real-world applications, such as understanding the forces acting on a spinning top, calculating the forces on a rotating shaft in a vehicle engine, or determining the forces needed to maintain balance on a bicycle.

5. What are some factors that can affect the force needed to maintain a 45° position in N Angular Kinetics?

The force needed in N Angular Kinetics can be affected by various factors, such as the mass of the object, the speed of rotation, and any external forces acting on the object, such as friction or air resistance.

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