Rotation Speed of Pulley - Introductory Physics - Solved Paper, Exams of Physics

Download Rotation Speed of Pulley - Introductory Physics - Solved Paper and more Exams Physics in PDF only on Docsity! Physics 8A Section 2 Midterm # 2 Paden he Your name November 7, 2002 210 (Shahed) Ri ji-i2pm Discussion session number / GSI name 1) DON’T OPEN THIS EXAM UNTIL INSTRUCTED TO BEGIN 2) Sit one seat away from anyone else. 3) Do all your work on the page (front/back) indicated for each problem. 4) Show all work; don’t just write an answer without showing your reasoning. 5) This is a closed book exam but calculators are allowed. 6) To simplify the math, take the acceleration due to gravity as g = 10 m/s”. 7) Possibly useful equations include: F =dp/dt=ma Te=1,,,, anh? p=mv K=1/210° Foemy/r F/A =E 6L/L X=Xj+Vot+l/2at F=GM,m/r* We Pk F=-dU/dx U=mgh G=7x10"Nm?/ke? K=1/2mv? Vee OOM TR)” t=la Mun = 6 x 10" kg l=mr R3, 20x 10°m t=rxF sdL fdt ‘ vy, A,=¥2 A, L=Iw p+ 1/2 pv’ +p gy=constant v=or 1 atmosphere = 10° Pa aear p (H,O) = 1 g/cc SCORING - we'll handle this space : ) 1) 20 2 2? 3) 4 5) TOTALI  1) A mass m, = 10 kg hangs at a distance h = 3 m above the floor from a massless rope that is wrapped around a frictionless pulley. The pulley’s mass m, = 20 kg is concentrated at its rim, which has a radius R = 2 m. What is the time that it takes for th when it is released? What is the kinetic ener. mass m, when it hits the floor? c) What is the rotatio f the pulley, when the mass hits the floor? runr beione esiity We ky ah 30 +: f v= maz 20g Fram g)Gm> eas = Ma we slaty 2 10(4.79(3) = Np (a2) + 2 (0) Aa = ON +52 294 3 15 vt wv? ib BY = Voy lage? a) lage ~ 3m = (44amsye 29.354 se -3* 4.43%. 494? 444.4543 =0 r= 135\ ») ‘eS =) a za KE = lam = iz (04.43) ieee ees ¢) wWrev we = Taam _ pa madl/ r am a  4) Earth is under attack from an alien civilization that shoots an asteroid at us from the edge of the universe. The asteroid has a mass m= 100 kg and an initial speed v = 10 km/s. a ee Mesrth os v a) What is the kinetic energy of the asteroid upon its impact with the Earth? b) Should this energy release affect the rotation of the Earth about its axis? (hint: consider the rotational energy of the Earth, remembering that the moment of inertia of a solid sphere I = 2/5 mR? ) =<. Mg= looky a) ‘KES = weM|S= 10,000ms he wie =A}q (v90)C10)000) e= 0 La Me= oxo kg De (ian +5\ WiG= O ois : » ms » rag fos I aie (yd) [i (400 Xrgjo0d) + OF yy Tearth= 2s me” Ne= |e m\s j a “= (4 ag Loxio4) ace wees | = Beene? iio cs -) ee jalmats) 5m Ile) 2 Poranonal Eneegy Farin = 1/2 Tu? cased) ) (ere) =a dno? IC! wnt), S—— 4( oo wyans) =e a(n 00 (0 2 be Avon )(98) td e341. 3 : 99) = Soy We . (sua?) 2a he Re “14 io S107 +4. aan0" Wd = SbFx0 7 + % 64x09 =. a as2now = - 9410 loo est ir snoud atecr tre veronory bic = 3 4- ba vo EaveThs pRiqinal eqeegy wis 50°F and now Hs veing HT with fre astepoid OF the Same €néwgy, “vad|s 2  5) Water is contained in a large diameter tank, which is sealed and held at a pressure P = 2 atmospheres. The top of the water in the tank is at a height h, = 10 m above the ground. The water flows through a hole in the bottom of the tank and through a frictionless pipe, out through a horizontal opening with an area A = 0.1 m’, at a height h, = 5 m above the ground, and open to the air. a) What is the horizontal distance from the end of the pipe that the water shoots out, before the water hits the ground? (you can use helpful approximations) oP par a Aeoam™ Pe 2arm = 2xK¢ hyziomn of Ate Warne ¥ 2 e Y Neu = Aeve Ppe= \orm= 1X07 paw ee NP? ve Se NE qe ett + A iy 7 Vivo Pet ned? ~eghs = Pp te eve +eghe & ee: a aie J ax (a8) (V0) = VA10"4 Ya 998) (vp }* Can 015) 299,800 = 149,900 +112 (993) Ve™ Wa A0D = M2(4B) wy" { 72 300 Vet 23mI\5 | vy Vr AN= Noyt —\2 at = 32 (eect? ee Yo = (\4:33)(3,3)