SPH4U: Lecture 8 Notes - The Burns Home Page

m m 1 2m ma 1 sin q1 2 sin q2gm1 m2q 1 q 2Special Case 3:m 1Lab configurationm 2Lecture 8, Act 2Two-body dynamics• In which case does block m experience a larger acceleration?In (1) there is a 10 kg mass hanging from a rope. In (2) ahand is providing a constant downward force of 98.1 N. Inboth cases the ropes and pulleys are massless.mma10kgaF = 98.1 NIf q 1 = 0 and q 2 = 90,ma 2( m m g1 2 )Case (1) Case (2)(a) Case (1) (b) Case (2) (c) sameSPH4U: Lecture 8, Pg 21SPH4U: Lecture 8, Pg 22aLecture 8, Act 2Two-body dynamics• In which case does block m experience a larger acceleration?In (1) there is a 10 kg mass hanging from a rope. In (2) ahand is providing a constant downward force of 98.1 N. Inboth cases the ropes and pulleys are massless.10kgm W =10kgm(a) Case (1) (b) Case (2) (c) sameamF = 98.1 NCase (1) Case (2)• Add (a) and (b):m W g = (m + m W )amWga m m• Note:WLecture 8, Act 2Solution• For case (1) draw FBD and write F NET = ma for each block:T = ma (a)(a)m W g -T = m W a(b)mT mWg m mWa10kg(b)mm W =10kgSPH4U: Lecture 8, Pg 23SPH4U: Lecture 8, Pg 24Page 6