Finding Equilibrium in a Weighted System

In summary, the problem involves determining the weight and angle needed for a block to be in equilibrium with a leg and cast that weigh 220N. The solution involves treating the leg and cast as a separate system and considering the ropes connected at the center of mass.
  • #1
twistedps
4
0

Homework Statement


Having trouble with this problem, can't figure it out! Please help me!
The persons cast is the green drawing (sorry by i was using ms paint)

The problem is as follows:
The leg and cast in the picture above weigh 220N (w1). Determine the weight w2 and the angle a needed so that no force is exerted on the hip joint by the leg plus the cast.

In case you can't make out the picture, the block on the left is 110N, and the angle is 40DEG on the left. w1 = 220N. the block on the right is w2. with angle a.

Thank you guys so much! I am rackin my brain here!
http://img82.imageshack.us/img82/8500/probrh0.th.jpg


Homework Equations


Not sure how to even out the two to figure this out, I am confused as where to start!


The Attempt at a Solution


I don't even know how to begin to setup this problem!
 
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  • #2
Not to be gratuitously violent, but conceptually cut off the leg and do the problem with just the leg and the ropes. The rest of the body is not doing anything. Note that the ropes are connected at the center of mass of the leg, which is the only way you can have no force on the hip.
 
Last edited:
  • #3
hrm, k, i think i get what your saying... i'll try this out! thanks!
 

FAQ: Finding Equilibrium in a Weighted System

1. What are Newton's laws of motion?

Newton's laws of motion are three physical laws that describe the relationship between a body's motion and the forces acting on it. The first law states that an object in motion will stay in motion unless acted upon by an external force. The second law relates the net force, mass, and acceleration of an object. The third law states that for every action, there is an equal and opposite reaction.

2. How do Newton's laws of motion apply to everyday life?

Newton's laws of motion can be observed in various aspects of everyday life. For example, the first law explains why objects keep moving in a straight line unless something stops them, like a car stopping at a red light. The second law is evident when you push a shopping cart, and it accelerates in the direction of the force. The third law can be seen when you walk, your feet push against the ground, and the ground pushes back, propelling you forward.

3. What is the difference between mass and weight?

Mass is a measure of the amount of matter in an object, while weight is a measure of the force of gravity acting on an object. Mass is constant regardless of location, while weight changes depending on the strength of gravity. For instance, an object that weighs 10 pounds on Earth would weigh less on the moon due to the moon's weaker gravity.

4. Can forces act on an object without causing motion?

Yes, forces can act on an object without causing motion. This is known as balanced forces, where the forces acting on an object are equal in size and opposite in direction, resulting in a net force of zero. In this case, the object remains at rest or continues to move at a constant speed in the same direction.

5. How are Newton's laws of motion related to each other?

The three laws of motion are interrelated and build upon each other. The first law sets the foundation for the second law, which explains how forces affect an object's motion. The third law shows that forces always come in equal and opposite pairs, further expanding on the concept of forces and motion. Together, these laws provide a comprehensive understanding of the relationship between forces and motion.

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