NSS MAGNETISM (URGENT!!)

(a) The magnetic force acting on QR is horizontal pointing towards the right.

(b) (i) Take moment about PS,
0.05g x (0.1/2).sin(theta) = 10 x 0.2 x 1 x B
hence, B = 0.01226.sin(theta)

(ii) B = 0.01226.sin(30) T = 0.00613 T



2011-11-27 09:35:04 補充：
Sorry..I made a mistake at (b)
The correct equation should be
0.05gx(0.1/2).sin(theta) = (10x0.2x1xB)x(0.1cos(theta)
i.e. B = 0.1226.tan(theta)

2011-11-27 09:36:26 補充：
(bii) B = 0.1226.tan(30) T = 0.071 T