Simple Steps to Solving Force-Related Problems

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To solve force-related problems effectively, begin by drawing a force-body diagram for each object involved. The sum of forces in a single force-body diagram equals zero only when the object is in equilibrium. For accelerating systems, the net force is defined by F=ma, emphasizing the importance of understanding vector directions. It's crucial to clarify conditions when discussing forces, as the equilibrium principle does not apply universally. Following these guidelines will enhance problem-solving skills in physics.
Da-Force
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This is actually from my teacher, he's a genius, and it works pretty much every single time :-)

No matter what situation... Draw a force-body diagram for every mass/object/thing that has a force acting on it.

The sum of the forces in each direction in a SINGLE FORCE-BODY diagram always adds to be zero.

Forces always come in pairs.

Label all forces and write the equation (if applicable) for each force.
Example: W = mg, T​

The net force of the system, if it is accelerating will be defined by the sum of all the forces on the system, F=ma.
To know when to add or subtract forces, make sure you understand forces are vectors and choose one direction as positive and the other as negative.​

Follow these rules, steps, guidlines, and you will be able to solve any force-related problem!

Hope this helps :-)
Da-Force

PS: Add comments if you want
 
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The sum of the forces in each direction in a SINGLE FORCE-BODY diagram always adds to be zero.

:confused:
 
Da-Force said:
The sum of the forces in each direction in a SINGLE FORCE-BODY diagram always adds to be zero.

Da-Force said:
The net force of the system, if it is accelerating will be defined by the sum of all the forces on the system, F=ma.

I believe you have just contradicted yourself here. Make sure your you specify you conditions, the former would be true only if the object is at equilibrium, i.e. stationary or moving with a constant velocity.

I was just wandering what you meant by single force-body diagram?

-Hoot:smile:
 
Da-Force said:
This is actually from my teacher, he's a genius, and it works pretty much every single time :-)

No matter what situation... Draw a force-body diagram for every mass/object/thing that has a force acting on it.

The sum of the forces in each direction in a SINGLE FORCE-BODY diagram always adds to be zero.

Incorrect. This is true only for an object in equilibrium.

[Edit: Sorry, I didn't see Hoot's response]
Anyway, this is a forum for people to ask questions.

This is not a place for one to post gems of wisdom. You can do that in a PF journal. Find the "Journal" tab at the top of the list. OTherwise, offer your help in response to specific questions here.​
 
Last edited:
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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