作者ventural (123)
站内TransPhys
标题[力学] 力学问题 想了好久
时间Fri Feb 9 10:42:03 2007
a solid uniform disk of mass 21 kg and radius 0.85m is at rest flat on a
fractionless surface . A string is wrapping around the rim of disk and a
constant force of 30N is applied to the string .The string dose not slip on
the rim .(Icm for disk is 1/2MR^2) when the disk has moved a distance 9m
1.how fast is it moving?
(A)2.6m/s(B)5.1m/s(c)10.1m/s(d)20.4m/s(e)none of the above
2.how fast is it spinning?
(a)3.0rad/s(b)6.2rad/s(c)11.9rad/s(d)20.4rad/s(e)none of the above
3.how much string(length) has unwrapped from around the rim?
(a)4.5m(b)9m(c)18m(d)36m(e)none of the above
不知道答案
拜托大家了
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