Private Study Questions Set 9 PDF

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This is a good lecture note, the lecture is on a weekly basis...

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ENG1001 Private Study Questions Set 9 ! ! ! Q1!The!man!pushes!on!the!300kg!crate!with!a!force!F.!The!force!is!always!directed!down!at!30°!from! the!horizontal!as!shown,!and!its!magnitude!is!increased!until!the!crate!begins!to!slide.!Determine!the! crate’s!initial!acceleration!if!the!coefficient!of!static!friction!is!μs=0.6!and!the!coefficient!of!kinetic! friction!is!μk=0.3.! !

! ! ! Q2 The!8000kg!car!at!B"is!connected!to!the!3500kg!car!at!A"by!a!spring!coupling.!Determine!the!stretch! in!the!spring!if!(a)!the!wheels!of!both!cars!are!free!to!roll!(i.e.!neglect!the!effects!of!friction!in!this! case)!and!(b)!the!brakes!are!applied!to!all!four!wheels!of!car!B,"causing!the!wheels!to!skid.!Take!μk(b)!=! 0.4.!Neglect!the!mass!of!the!wheels. ! !

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! Q3 The!6000kg!dragster!is!traveling!with!a!velocity!of!125m/s!when!the!engine!is!shut!off!and!the! braking!parachute!is!deployed.!If!air!resistance!imposed!on!the!dragster!due!to!the!parachute!is!FD = (6000+0.9v2)N,!where!v!is!in!m/s,!determine!the!time!required!for!the!dragster!to!come!to!rest.! !

! ! ! ! Q4!The!buoyancy!force!on!the!5000kg!balloon!is!F!=!6kN,!and!the!air!resistance!is!FD = (100v) N,! where!v!is!in!m/s.!Determine!the!terminal!or!maximum!velocity!of!the!balloon!if!it!starts!from!rest.! !

! ! ! Q5 Determine!the!acceleration!of!the!system!and!the!tension!in!each!cable.!The!inclined!plane!is! smooth,!and!the!coefficient!of!kinetic!friction!between!the!horizontal!surface!and!block!C"is!μk,C#=#0.2. ! !

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