求物理帝解答!给个得数!
A54-kgcrateisplacedonaninclinedramp.Whentheangletherampmakeswiththehorizontalisincreasedto25.0°thecratebeginstoslidedownward.
(a)Whatisthecoefficientofstaticfrictionbetweenthecrateandtheramp?
(b)Atwhatangledoesthecratebegintoslideifitsmassisdoubled?