Seesaw: simple statics problem?

In summary, the conversation discusses a simple statics problem involving a seesaw with a uniform length and weight, where two individuals of different weights are positioned on either end. The question is to find the weight of one individual based on the information provided. The solution involves finding the point of maximum torque and balancing the clockwise and counter-clockwise torques.
  • #1
ninjagowoowoo
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Seesaw: simple statics problem?

Q:
A uniform seesaw is of length 3.90 m and weighs 235 N. The seesaw is pivoted about a point on its bottom surface and the location of this pivot along the length of the seesaw can be adjusted as far as a distance 0.170 m from the center of the seesaw. Little Karen, who weighs 440 N, has her center of gravity over the right end, with the seesaw set so she exerts the most torque about the pivot. The seesaw balances horizontally when Elwood has his center of gravity is a distance 0.160 m from the left end. Both have their feet off the ground.

I have no idea what's up with this problem. I figured that we could just put the pivot in the exact center of the seesaw and then use that the net torque must be zero. So basically it'd be 1.95(Karens radius) times 440 (karens weight) is equal to 1.79 (Elwood's radius = 3.90/2 - 0.16) times Elwood's weight. So 1.95(440)=1.79(W). Since the pivot is in the center of the seesaw, the weight of the seesaw would just cancel itself out. Any help would be greatly appreciated.
 
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  • #2
What's the question? Is it to find Elwood's weight?

If so, first find the point where the seesaw is pivoted.It's given that Karen exerts the most torque about the pivot. You also know that Torque=rxF. So where should the seesaw be pivoted for Torque(and hence 'r') to be maximum?

Once you find that, balance the clockwise and counter-clockwise torques, and you will be able to get Elwood's weight.
 
  • #3
OH, thanks a lot. I missed that little detail.
 

1. What is a seesaw?

A seesaw is a simple machine consisting of a long plank balanced in the middle on a fulcrum. The plank has two seats at either end where people can sit, and by pushing off the ground with their feet, they can cause the plank to tilt up and down.

2. How does a seesaw work?

A seesaw works based on the principle of torque and balance. When two people sit on opposite ends of the plank, their weight creates a downward force on either side of the fulcrum. As long as their weights are equal, the seesaw will remain balanced. However, if one person is heavier than the other, the seesaw will tilt towards the heavier person.

3. What is static equilibrium?

Static equilibrium is the state in which an object is at rest and all forces acting on it are balanced. In the case of a seesaw, this means that the weight of the people on either end of the plank is equal, and the seesaw is not moving.

4. How do you calculate the weight distribution on a seesaw?

The weight distribution on a seesaw can be calculated by using the formula: W1 x D1 = W2 x D2, where W1 and W2 are the weights of the people sitting on either end of the seesaw, and D1 and D2 are the distances of their weights from the fulcrum. This formula assumes that the seesaw is in static equilibrium.

5. Can a seesaw be used to lift objects?

Yes, a seesaw can be used to lift objects as long as the weight distribution is balanced. This is known as a lever, and seesaws are a type of first-class lever. By placing the object to be lifted at one end of the seesaw and applying force at the other end, the seesaw can be used to move the object upwards.

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