How to Calculate Work from F vs x Graph?

Therefore, the total work is W = W1 + W2 = ?In summary, the problem is to find the work done when the applied force changes with position along the x-axis and the graph of force vs. displacement is irregular. The work is equal to the area between the graph and the x-axis, which can be calculated by finding the area of the two triangles formed by the graph and the x-axis. The total work is the sum of the work done from x=-2 to x=0 and from x=0 to x=2.
  • #1
MLash

Homework Statement


x1= -2, x2= 2

F1= 1, F2= -2

Graph in uploaded image

Homework Equations


w= F* del x* cos(theta)

The Attempt at a Solution


I am trying to find the area under the points of F and x but it has an irregular shape and i don't know what to do? Should i do w= (f1-f2)(del x)?[/B]
 

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  • #2
MLash said:
w= F* del x* cos(theta)
The general form of work is
$$W=\int_{x_{1}}^{x_{2}}\mathbf{F}\cdot d\mathbf{x}$$
Thus if you have a graph of ##F## vs. displacement. The work is the area under the curve from the staring position ##x_{1}## to the final position ##x_{2}##.
 
  • #3
MLash said:

Homework Statement


x1= -2, x2= 2

F1= 1, F2= -2

Graph in uploaded image

Homework Equations


w= F* del x* cos(theta)

The Attempt at a Solution


I am trying to find the area under the points of F and x but it has an irregular shape and i don't know what to do? Should i do w= (f1-f2)(del x)?[/B]
No, the applied force changes with the position. And both the displacement and the force are along the x axis.
The work is equal to the area between the graph of force and the x axis. You have to calculate the area of both triangles, the blue one and the yellow one. In case of the blue triangle, both the force and the displacement are positive, so cos(theta)=? W1=?
In case of the yellow triangle, the force is negative, the displacement is positive, so cos(theta)=? W2=?
The whole work is the sum of the works done from x=-2 to x=0 (W1) and from x=0 to x=2 (W2) .
upload_2017-10-25_6-13-19.png
 

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1. What is work done from F vs x graph?

Work done from F vs x graph is a measure of the energy transferred to or from a system by a force as it moves through a displacement in the x-direction. It is represented by the area under the force vs displacement graph.

2. How is work calculated from a F vs x graph?

Work is calculated by finding the area under the force vs displacement graph. This can be done by dividing the graph into smaller rectangles and calculating the area of each rectangle, then adding them together.

3. What does the slope of a F vs x graph represent?

The slope of a F vs x graph represents the force acting on the system at a particular point. It can also be interpreted as the rate of change of work over displacement.

4. Is work done positive or negative on a F vs x graph?

Work done can be positive or negative on a F vs x graph, depending on the direction of the force and displacement. Positive work is done when the force and displacement are in the same direction, while negative work is done when they are in opposite directions.

5. How can a F vs x graph be used to calculate the work done by a varying force?

A F vs x graph can be used to calculate the work done by a varying force by finding the area under the graph using integration. This allows for more accurate calculation of work when the force is not constant over the displacement.

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