Does Normal Force Do Work in Vertical Motion?

[Vontox7]

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.

 

[Spinnor]

E initial = E final

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

You can figure out all three.

?

 

[Vontox7]

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.

 

[Redbelly98]

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?

 

[asteriatic]

I can provide some clarification and guidance on the concept of work done by normal force in this scenario. Work is defined as the product of force and displacement, so in order to calculate the work done by each force, we need to determine the force acting on the object and the displacement it undergoes. In this case, the rope is pulling the object up with an applied force, while gravity is acting down with its own force. The normal force, which is the force exerted by the surface the object is resting on, is also present and has a magnitude equal to the weight of the object.

To find the work done by each force, we need to first calculate the net force acting on the object. This can be done by subtracting the force of gravity (mg) from the applied force. In this case, the net force would be 4.4 N up. Next, we can calculate the work done by the net force by multiplying the net force by the displacement (9.9 m) to get a value of 43.56 J. This is the total work done on the object by all the forces.

To address your confusion about including the normal force and gravitational force in the displacement calculation, it is important to note that displacement is the change in position of an object. In this scenario, the object is moving vertically, so the displacement is measured in the vertical direction. This means that the displacement will only include the vertical distance traveled, not the distance traveled along the surface due to the normal force. Therefore, when calculating displacement, we do not need to consider the normal force or gravitational force.

I hope this helps to clarify the concept of work done by normal force in this scenario. Remember, work is the product of force and displacement, and the net force and displacement should be used when calculating the total work done. Keep practicing and studying, and don't hesitate to ask for help when needed. Good luck!