dx dy bwcosat v==-aasina t x dt dt 当B点(0,b)t=T/4, 0 C U=v C X mv=ma 2 a=-adcosatitbwsino --@-lacosati+ bsin atj F=ma=-mo2 r 目录结束当B点 (0,b) t = T/4， dy dt vy = = aωsinωt t vx x d d = = bωcosωt vy = 0 vx = aω v = vx = aω mv 2 1 2= maω 2 1 2 2 a = i b j 2 cos t sin t 2 aω ω + ω ω = ( i b j ) 2 ω acosωt + sinωt = ω2 r F = m a = ω2 m r 目录 结束