## hermionegranger 3 years ago Pls Explain motion in a magnetic field ,when velocity is at an angle with the field .

1. hermionegranger

??

2. Ishaan94

Okay, Can you tell me the Magnetic Field Force ? I forgot sorry

3. hermionegranger

F = q (V x B )

4. Ishaan94

Hmm Right so do you know cross product ?

5. hermionegranger

i'm a bit confused about it

6. Ishaan94

hmm I won't be able to explain through words but I will try finding some videos fro you. btw do you know about mit ocw ?

7. hermionegranger

nope

8. hermionegranger

what is that?

9. Ishaan94
10. hermionegranger

oh thanks i'll check it out :)

11. Ishaan94

if you have any doubts please do post them I have to study magnetic field too so your doubts can be helpful to me. sorry If I sound mean

12. hermionegranger

no not at all :) .. i'm going through those videos .. it covers most of my portions ...thank you so much

13. Ishaan94

: ) no problem

14. hermionegranger

|dw:1316022392752:dw| can you tell me how we get v || =$v \cos \theta$ and v perpendicular = $v \sin \theta$

15. hermionegranger

are u here ishaan ?

16. Ishaan94

yea I am ! :D

17. hermionegranger

can you tell me how we get v || =vcosθ and v perpendicular = vsinθ

18. Ishaan94

Okay...I will try |dw:1316022839246:dw|

19. Ishaan94

I think Parallel, Vertical all are taken with respect to x-axis so $$v_{parallel}$$ is $$v\cos\theta$$

20. hermionegranger

the angle θ is b/w your vsinθ and v

21. Ishaan94

hmm like this |dw:1316023174038:dw|

22. hermionegranger

yes

23. Ishaan94

Okay ..|dw:1316023222420:dw|

24. hermionegranger

how did u get it ? :(

25. Ishaan94

hmm do you know about sin ratios hmm okay Let me try again $sin\theta = \frac{Perpendicular }{Hyp}$ so now try to apply this in the triangle the upper triangle

26. hermionegranger

ok let me see..

27. Ishaan94

|dw:1316023483789:dw|

28. hermionegranger

Got It Got It :)

29. Ishaan94

Yay!!

30. Ishaan94

$\cos\theta =\frac{base}{hyp}$

31. hermionegranger

thanks a ton :) yea i know it :)

32. hermionegranger

now i'll never forget it :)

33. Ishaan94

!! yay (Again ) :D

34. hermionegranger

ok so vcosθ is Magnetic field and it is given in my notes that thus charge q will hav two motions linear and circular and hence resultant path is helix its axis along direction B |dw:1316023925945:dw|

35. hermionegranger

|dw:1316024026575:dw|

36. hermionegranger

how is it helix ? and how does it have linear and circular motions ?

37. Ishaan94

hmm I think that is where electric field comes to effect

38. Ishaan94

magnetic field makes it to move in circular motion but electric field makes it to move froward

39. Ishaan94

so hence helix is formed

40. hermionegranger

ok thankyou sooooooooooooooooooooooooooooo much for your help yaaayyyy :)

41. physics.commando

Resolve the velocity into two components: one component parallel to the magnetic field; the other component perpendicular to it. The (assumed charged) particle will maintain the velocity that is parallel to the magnetic field, but will simultaneously move in circles in the plane perpendicular to the magnetic field. The combined effect is that it will "spiral" in a helix "following" the magnetic field.