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coursehero_exam2studyguide - to the mass 3 rd action...

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Ball dropping. What forces acting on ball? a mg F=ma mg=ma a=g=9.8m/s 2 Mass hanging from ceiling. What is tension in string? T mg a=0 F=ma T is positive T-mg=ma=0 T=mg Frictional force: If there’s degree involved: 3 forces along x: ff-uphill F-up mg-down y:N-up a-down x: F x = ma x mgsinθ - f f - F=ma f f = μN y: N – mgcosθ = ma = 0 N=mgcosθ No mass, no friction, same accel: m 1 : N-up m1g-down a-right T-right x-pos x: T=m 1 a m 2 : T-up a-down m2g-down y-pos. y: m 2 g – T=m 2 a Centripetal accel: F=ma c a c =v 2 /r obj turn T+mg=ma c T+mg=m(v 2 /r) Universal gravitation: F=(Gm 1 m 2 )/r 2 Newton’s laws: law of intertia: constant unless acted upon external force. 2 nd : F=ma A body of mass subject to F undergoes an accel that has the same direction as the force and a magnitude that is directly proportional to the force and inversely proportional
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Unformatted text preview: to the mass. 3 rd : action / reaction– forces equal in magn. and opposite in direction. Torque=rotational force ω=ang vel. θ=revolutions 2πrad per rev 2πr=circumf v=2πr/T T:time int α= ω /t v=r ω a=r α ang disp constant speed: Δ θ = ω Δ t ang disp constant accel: Δ θ= ω i Δt + 1/2 α Δ t 2 change in vel at constant accel: Δ ω =α Δ t CCW speeding up: w>0 a>0, CCW slow: w>0 a<0, CW slow(w=neg, a=pos): w<0 a>0, CW speed(w=neg,a=neg): w<0 a<0. Wrench prob: find r and F τ=rF τ=rFcosθ τm 2 =rF 2 τm 1 =rT 1 τm2=rT2 I pully =1/2MR 2 (given) τ=r(T 2-T 1 )=1/2MR 2 α Ruler question (static equil): F=0 and τ=0 N-m 1 g-mg-1/2m 1 g=0...
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This note was uploaded on 07/07/2011 for the course PHYS 209 taught by Professor Staff during the Fall '08 term at Clemson.

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