Work of an Object moving down Inclined Plane

AI Thread Summary
The discussion revolves around calculating the work done by a suspended mass and gravity as a block moves down an inclined plane. A 208g weight is attached to a block on a 30-degree incline, with the block weighing 474g and moving a distance of 24.7cm. Participants express confusion about the setup, particularly regarding the introduction of the car and the need for clarity in the experiment's description. The concept of negative work is debated, as the force from the suspended mass acts against the direction of motion. Emphasis is placed on using conservation of energy and performing algebraic calculations before substituting numerical values.
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Homework Statement


Experiment set up.
A 208g weight is attached via a pulley system to a block on an inclined plane. What is the work done by the suspended mass as the car is lowering at a constant velocity? And work done by gravity?

Distance weight moves down - 24.7cm
Incline is 30 degrees

Homework Equations


F=ma
w=Fdcos(\theta)


The Attempt at a Solution


So, in this case, work would be negative, right? Because the direction of the force from the suspended mass is going UP the incline, and the direction of moment is DOWN the incline?

The block is 474g

I'm not sure where to start. If I use the basic work formula and do
\(-208*980)*24.7?
 
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The thing losing energy is doing the work.
The description of the experiment is incomplete - we are told about the suspended mass and then some car is introduced out of nowhere... but it looks like you are expected to use conservation of energy. Your descriptions of what you have tried are also incomplete so it is not clear what you have done.

Try expressing your working symbolically - do all the algebra before you put numbers in.
 
Simon Bridge said:
The thing losing energy is doing the work.
The description of the experiment is incomplete - we are told about the suspended mass and then some car is introduced out of nowhere... but it looks like you are expected to use conservation of energy. Your descriptions of what you have tried are also incomplete so it is not clear what you have done.

Try expressing your working symbolically - do all the algebra before you put numbers in.

Sorry, I wrote it really quickly.

The setup was an inclined plane with a pulley system which was set off the leg of the triangle. The pulley system was attached to the car. We had to set a weight on the pulley so that the car would go down the plane with a constant velocity.

I'm really not sure what to do. The car is moving down the car, therefore losing potential energy. If work can be defined as the difference in U.

So, if then ΔU= (474*980*12.5)-(474-980*0)= 5,806,500 erg?
 

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