How Do You Solve a Newton's Second Law Problem with a Free Body Diagram?

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Homework Help Overview

The discussion revolves around applying Newton's Second Law using a Free Body Diagram (FBD). Participants are tasked with determining the gravitational force (Fg), net force (Fnet), and mass (m) based on the provided FBD and equations.

Discussion Character

  • Exploratory, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to equate various equations but expresses uncertainty about the process. Some participants suggest using the relationship between net force, mass, and acceleration, while others question the accuracy of significant digits in the final calculations.

Discussion Status

Participants are actively engaging with the problem, providing guidance and checking the calculations. There is a mix of approaches being explored, with some participants offering insights on the equations involved and others verifying the results without reaching a consensus.

Contextual Notes

There is mention of specific values such as acceleration and forces acting on the mass, but the discussion also highlights potential issues with significant figures and the need for clarity in the calculations.

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Homework Statement


There is an attachment of a FBD, and you have to solve for the following:
Fg=?
Fnet?
Mass=?

The Attempt at a Solution


I know you will have to equate equations, but I don't know how to go about doing this.
I do know that Fg= m x 9.8, I isolated various equations and subbed them into each other and got no answer.
 

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Remember that the net force = mass X acceleration.
You have the acceleration, you have the two forces acting on the mass, and mass m.

You are almost there.
 
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barryj said:
Remember that the net force = mass X acceleration.
You have the acceleration, you have the two forces acting on the mass, and mass m.

You are almost there.

Fnet=ma
-Fg+F=ma
-9.8m+110 = m
-10.8m=-110
m=10.2kg

Fnet=-Fg+F
=-9.8m+110
=-9.8(10.2)+110
Fnet=10.04N

a= Fnet/m
a=10.04/10.2
a=0.98 m/s/s

Is this correct?
 
Looks good. However, you might use some more significant digits as the last part, a should be 1.0 as given.
 

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