Does Normal Force Do Work in Vertical Motion?

AI Thread Summary
The discussion revolves around the confusion regarding the work done by various forces on a 2 kg object being pulled upward. The user calculated the displacement as 9.9 m and found the work done by the applied force, normal force, and gravity, resulting in a total mechanical work of -0.678 J. There is uncertainty about how to correctly account for the normal force and gravitational force when calculating net work in vertical motion. Participants question whether a normal force is present during upward acceleration and clarify that it typically does not do work in this scenario. The conversation highlights the importance of understanding the roles of different forces in mechanical work calculations.
Vontox7
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Hello,
I have become very confused after i tried to solve this question.
A rope pulls a 2 kg object straight up, accelerating it from rest at 2.2 m/s^2 for 3 seconds.
they want the work done by each force acting on it.
Ok i found the displacement as 9.9 m up. Then i found out that the applied force does 43.56 J and that Fn does 150.678 J and gravity does 194.238 J .

Then they ask for the total mechanical work done. I just added the works and got -.678 . Then they ask for the net force which is 4.4 N up and work done by the net force which is 43.56 J.

I am confused about finding the net work when fg,fn, fapp are involved what am doing wrong. Also when solving other questions do i include fn and fg when the displacement is vertical?

Please help and thank you. i would add more detail but i got no time to study.
 
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E initial = E final

0 = - mg*X + F*X + mV^2/2

You can figure out all three.

?
 
I am sorry but i don't understand your formula. yes, i know that initial potential and kinetic energy equal the final but the next line i don't understand what it is nor how it can help.
 
Vontox7 said:
Hello,
I have become very confused after i tried to solve this question.
A rope pulls a 2 kg object straight up, accelerating it from rest at 2.2 m/s^2 for 3 seconds.
they want the work done by each force acting on it.
Ok i found the displacement as 9.9 m up. Then i found out that the applied force does 43.56 J and that Fn does 150.678 J and gravity does 194.238 J .

Then they ask for the total mechanical work done. I just added the works and got -.678 . Then they ask for the net force which is 4.4 N up and work done by the net force which is 43.56 J.

I am confused about finding the net work when fg,fn, fapp are involved what am doing wrong. Also when solving other questions do i include fn and fg when the displacement is vertical?

Please help and thank you. i would add more detail but i got no time to study.
What is Fn, a normal force? Are you sure there is a normal force acting on the object while it is accelerating upward?
 

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