Questions on EMI( electromagnetic induction)

Hello...I'm quite confused about questions that have variations for EMI...

1) for the formular E(induced emf) = BLv,
When do you know if we need to consider horizontal or vertical velocity?

Hello...I'm quite confused about questions that have variations for EMI...

1) for the formular E(induced emf) = BLv,
When do you know if we need to consider horizontal or vertical velocity?

It will depend on the specifics of the question. You need to be quite good at 3D visualisation to do well with this type of question IMO.
You're interested in the rate of 'flux cutting' so it's the velocity perpendicular to the magnetic field lines that you're interested in.

You need to consider the component perpendicular to the magnetic field lines

Thank you!! I have an additional question regarding the same problem...(diagram attached above)...
The question is : to find the mass of x
Of course there are earlier necessary parts to arrive at finding the mass, but I don't understand the solution on how they equated the two force components
Solution:

Attachments are not available

Attachments are not available

Solution picture:



Sorry can't seem to attach both pictures in one post ><