How Do You Integrate (dx/dt) dx in Physics Problems?

In summary, to solve the integral ∫ b (dx/dt) ⋅ dx, you can express dx/dt as a function of x and then integrate. Alternatively, you can substitute dx for v dt and integrate the resulting equation, where v represents velocity.
  • #1
danunicamp
7
0
Good Night,

Can someone please tell me how to do: ∫ b (dx/dt) ⋅ dx ?

Like in the work done by a force which is proportional to the velocity (like drag). I tried to change dx to v dt but couldn´t go much further.

Thank you in advance.
 
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  • #2
If you write ##v=\frac{dx}{dt}## then you have ##dx=v\,dt## and you can write your equation as ##\int b\,v^2 dt##.
 
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Likes danunicamp
  • #3
Note that it is sometimes easier to express ##dx/dt## as a function of ##x## rather than ##t##. In these cases, you can simply integrate that function. You really cannot get any further without having a specific integral to do. Note that such a problem should be posted in the homework forums with the template properly filled in, including your own attempt and the full problem statement.
 
  • #4
andrewkirk said:
If you write ##v=\frac{dx}{dt}## then you have ##dx=v\,dt## and you can write your equation as ##\int b\,v^2 dt##.
Thank you very much
 

Related to How Do You Integrate (dx/dt) dx in Physics Problems?

1. What does "integrate (dx/dt) dx" mean?

Integrating (dx/dt) dx refers to finding the antiderivative of the function dx/dt with respect to x. This means finding a function whose derivative with respect to x is equal to dx/dt.

2. Why do we need to integrate (dx/dt) dx?

Integrating (dx/dt) dx can help us solve problems that involve rates of change over time, such as finding the displacement or velocity of an object. It is also a fundamental concept in calculus and is used in many applications in physics, engineering, and economics.

3. How do you integrate (dx/dt) dx?

To integrate (dx/dt) dx, we use the power rule for integration, which states that the integral of x^n is (x^(n+1))/(n+1) + C, where C is the constant of integration. In this case, we can rewrite (dx/dt) dx as (d/dt)(x^2)/2 and use the power rule to obtain x^2/2 + C.

4. What is the difference between integrating (dx/dt) dx and dx/dt?

The main difference between integrating (dx/dt) dx and dx/dt is that integrating (dx/dt) dx gives us a function, while dx/dt is simply a derivative. Integrating (dx/dt) dx allows us to find the original function that was differentiated, while dx/dt gives us the rate of change of that function.

5. Can you provide an example of how to integrate (dx/dt) dx?

One example of integrating (dx/dt) dx is finding the displacement of an object with a velocity of dx/dt = 2t, where t represents time. We integrate (dx/dt) dx to obtain the displacement function x^2 + C, where C is the constant of integration. We can then use this function to find the displacement at any given time t.

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