How to Calculate Work from F vs x Graph?

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SUMMARY

The calculation of work from a force versus displacement graph involves determining the area under the curve between specified points. In this case, the points are x1 = -2 and x2 = 2, with corresponding forces F1 = 1 and F2 = -2. The work done is calculated by integrating the force over the displacement, represented as W = ∫(F dx) from x1 to x2. The area consists of two triangles: one where the force is positive (W1) and another where the force is negative (W2), with the total work being W = W1 + W2.

PREREQUISITES
  • Understanding of integral calculus, specifically the concept of definite integrals.
  • Familiarity with force and displacement concepts in physics.
  • Knowledge of calculating areas of geometric shapes, particularly triangles.
  • Ability to interpret graphical data and apply it to physical equations.
NEXT STEPS
  • Study the principles of definite integrals in calculus.
  • Learn how to calculate areas under curves using integration techniques.
  • Explore the relationship between force, displacement, and work in physics.
  • Practice solving problems involving irregular shapes in force versus displacement graphs.
USEFUL FOR

Students studying physics, particularly those focusing on mechanics, as well as educators and tutors seeking to enhance their understanding of work calculations from graphical data.

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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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}##.
 
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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