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
Messages
13
Reaction score
0
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.
 
Physics news on Phys.org
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?
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

Work done by a normal force (or rather, work NOT done)
2
Replies
57
Views
4K
Work done by a balloon that is rising
Replies
8
Views
722
Forces involved in principle of virtual work
Replies
2
Views
707
About work done through exercise (push ups)
Replies
4
Views
3K
Questions Regarding a Cat Going Up a Ramp
2
Replies
56
Views
3K
Finding the work done by a block
Replies
4
Views
3K
About Work done when velocity is constant
Replies
12
Views
4K
How do I find the work done for a 100 N downward force?
Replies
4
Views
2K
Why does the logic of negative acceleration not always indicate negative work?
Replies
7
Views
2K
Distribution of Energy when work is done on a system of 2 masses connected by a spring
Replies
17
Views
1K

Hot Threads

Recent Insights

Back
Top