2.转动之载流线圈 M=m×B do不e M=ISBsin o 转动d0 ?? d4=-BIS sin pdo .do>0,dA<0 dA=IBSd(coso)=Id(BS cosp)=Idp2. 转动之载流线圈 BmM r r r ×= = ISBM sinϕ d = −BISA ϕdsin ϕ ??? Q ϕ > A < 0d ,0d ϕ ϕ d)cos(d)(cosdd Φ m = IBSA = BSI = I 转动 dϕ dϕ