# Find the induced electromotive force (epsilon)

1. Mar 16, 2017

### Xhulio644305

it is something like this but instead of the rectalve contour iswith the angle 37 degree!!!!! View attachment 114624 1. The problem statement, all variables and given/known data
the speed of the slide is 0.16 m/s
the length of the slide is 0.14 m
the angle of the contour is 37 degree

2. Relevant equations
inducted electromotoric force=-delta phi/delta time
phi=induction(B)*surface*cos alpha (alpha=0 degree)

3. The attempt at a solutionhttps://drive.google.com/file/d/0BxmarOZtFg5FdEJDWkNaRnVZX00/view?usp=sharing

Last edited: Mar 16, 2017
2. Mar 16, 2017

### Staff: Mentor

1. Your problem description is too vague. "something like this" is not good enough. There's no way to know what your 37° angle pertains to.

2. Your image of your attempt at solution is all but illegible (too dark, out of focus). If necessary, type in your solution and only provide images for diagrams.

3. Mar 16, 2017

### Xhulio644305

#### Attached Files:

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4. Mar 16, 2017

### Staff: Mentor

It looks like the slider will lose contact with the two arms of the contour immediately after it passes the points AC. Is that intended?

Since the rate of change of the area of the closed loop will change with time, the EMF will change with time, too. Is there a particular instant in time or position of the slider for which you need to find the EMF?

You need to take your time to thoroughly prepare your problem description so that others can quickly and easily understand the details.

5. Mar 16, 2017

### Xhulio644305

The slider will continue to to slide (mayby it can stretch?? I dont know ,but im pretty sure that's not the case here) we have explained before in class what happens in a rectangle contour (the surface becomes l*dt*v and dt is being simplyfied with dt down and epsilon becomes -Blv) this is the exact thibg but ibstead of the S=l*dt*v it is more complicated because we should find the surface of the triangle above (right triangle with 37degree abgle ) this surface + the surface of yhe rectanglr should give a surface which has an dt inside (this dt sbould the be simplified with the dt down and should give the answer but this is fifficult to get a firmula with only one dt (this is mostly a trigonometric exercisr) si pls help because im really stuck (my teacher gave it only to me this exc. Causev im the best in my class and i cant let her down)

Last edited by a moderator: Mar 16, 2017
6. Mar 16, 2017

### Staff: Mentor

It looks like you want to find the EMF at the specific instant that the line AC is 14 cm in length. Suppose that at that instant that the two legs of the right angle triangle are x and y, with y being coincident with the line AC. How might you solve for x given the angle and value for y?

Then, what's the area of the triangle in terms of x?