Centripetal force and total force?

AI Thread Summary
The discussion revolves around calculating the centripetal force on a child swinging on a swing and determining the total force exerted by the ropes at the lowest point of the swing. The centripetal force can be calculated using the formula F = mv^2/r, where the child’s mass is 25 kg and the swing's radius is 2.00 m with a speed of 4.0 m/s. The confusion arises regarding the term "total force," which is clarified to refer to the tension in the rope at the lowest point, not the net force. The relationship between centripetal force, tension, and gravitational force is established as Fc = Ft - Fg, leading to a straightforward calculation for tension. Understanding that "total" simply refers to the force exerted by the ropes resolves the initial confusion.
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Homework Statement


A 25 kg child is on a swing, which has a radius of 2.00 m. If the child is moving 4.0 m/s at the bottom of one swing, what is the centripetal force exerted by the ropes of the swing on the child? What is the total force exerted by the ropes when the swing is at its lowest point?

Homework Equations


a = v^2/r

F = mv^2/r

The Attempt at a Solution



I have no problem with the first part of the question. You just use F = mv^2/r to figure out the centripetal force. However, I am not sure how to get the "total force." I know which way the tension is directed and everything. I'm just not really sure what total force is referring to. Any help would be greatly appreciated.

Thanks.
 
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Draw the free body diagram. What is causing the centripetal force?

Everything is easier because the problem asks you about the lowest point, so forces either point up or down.
 
The word "total" isn't necessary in that question. You can just as well think of it as "What is the force exerted by the ropes when the swing is at its lowest point?"
 
edit: nvm
 
So what it is asking for is basically the tension in the rope? If so, that is easy.

Fc = Ft - Fg

Solve for Ft.

The word "total" was throwing me off. I was convinced it meant Net force or something.
 
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