XF.0 205PHYS-205(3) (Kaldon-21354) Name _______S A M P L E __ F I N A L __ E X A M____WMU - Spring 1999 Final Exam - 200,000 points + 40,000 ¶ points Check-Out: Q X T ___6/22/1999•Rev.5c·04/09/2006•r5dState Any Assumptions You Need To Make – Show All Work – Circle Any Final AnswersUse Your Time Wisely – Work on What You Can – Be Sure to Write Down EquationsFeel Free to Ask Any Questions¶2a ¶2b ¶2c ¶2eWorld’s Fastest Human (Self-Powered, On-Foot) (50,000 points)1.) 9.79 seconds. That’s where 24 year old Maurice Greene recently set theworld’s record in the 100 meter dash at a track meet in Athens, Greece.(a) Find the average speed of Mr. Greene during his run.(b) Sprinters need to get up to near their top speed injust a few strides. If Mr. Greene goes from rest to 9.00 m/s in a distance of 5.00meters, find his acceleration. What assumption must you make to solve thisproblem?At this level of competition, sprinters use starting blocks to get themselves moving. The vector force rF1is applied at a standard angle of 220°. This is the force that the runner applies to the starting block. (c) Inwhat direction does the force rF2, the force on the runner, point? (d) And why?(e) Find the magnitude of the force F2. Let m = 97.9 kg. In order tosimplify the physics, do NOT use a Free Body Diagram – what partof the force can we find from the information on this page?Physics 205 / Final Exam Spring 1999 Page 2Odds and Ends (50,000 points)2.) ¶(a) A block of mass 50.0 kg slides along the floor on a frictionless layer of oil, with a kinetic energyof 625 J. Unfortunately, the oil runs out and friction begins for form: mkLx=0 500., where L is thestopping distance for the block. Find L.A velocity has an x-component of vx(t) = C t5 , where C = 15 m/s6 . At t = 3.21 sec find ¶(b) ax and¶(c) x. Assume x0 and ax0 are both zero.(d) Two masses, m1 and m2, are connected over a real pulley with moment of inertia, I, and radius R, andwhere m1 < m2 . Setup the Free Body Diagrams for m1 and m2, and the Free Rotation Diagram for thepulley. You must indicate which way the masses and the pulley intendto move, when the masses are released from rest. There is no frictionin this problem.¶(e) There is talk of building “elevators” that might take one into space. Imagine a steel wire stretchingfrom the ground to 100,000 km above the ground. The pressure on the bottom of a column of steel wouldbe P = rgh under ordinary circumstances, but g is not a constant here. To find the pressure from theweight of the steel on the wire above, you need to integrate Pgrdrrr=zr ()12, where g(r) is from Newton’sUniversal Law of Gravity. r1 is the radius of the ground, r2 is the radius of the orbit. Earth has a mass of5.98 x 1024 kg and a radius of 6378 km. G = 6.67 × 10-11 N·m²/kg². rsteel = 7130 kg/m³.Physics 205 / Final Exam Spring 1999 Page 3Ta-Dah!!! (50,000 points)3.) A fancy trick is to take a tablecloth and yank it out from underneaththe dishes on a table, without breaking anything. Consider the plate, m =0.425 kg, and with coefficients of friction between the plate andtablecloth of 0.100 and 0.150 respectively. Find (a) the maximum acceleration that the table cloth canmove to the right such that the plate travels with the tablecloth.(b) Find the maximum constant speed that the table cloth can move to the right such that the plate travelswith the tablecloth.(c) Part of the secret of the trick is to yank the tablecloth such that it is moving very fast. Find the value ofthe kinetic friction force between the plate and tablecloth.(d) If the tablecloth is snapped off the table in 11.0 ms (0.011 sec), how far does the plate move?(e) If the trick is done badly, the plates and glassware will all crash to the ground where they smash andshatter. Are the forces that destroy these plates and glasses conservative forces? Why or why not? Andwhat one Physics word best describes all these ruined table settings?Physics 205 / Final Exam Spring 1999 Page 4Heigh-Ho, Heigh-Ho, It’s Haul the Water We Go… (50,000 points)4.) One gallon (U.S.) of water is 3.80 liters. Since there are 1000 L in 1.00 m³,then 1.00 gal. = 3.80 × 10-3 m³. (a) Find the mass of this much water.(b) Imagine that we have a bucket (m = 0.250 kg) with 1.00 gal. of water in it, and we wish to raise it 35.0meters in 10.0 seconds. Find the change in the potential energy of the bucket.(c) Find the kinetic energy of the bucket.(d) Find the total work that the engine has to do, and the power it has to deliver.(e) If actual efficiency, eactual , of the heat engine that is hauling up the bucket is 42.2% (0.422), then howmuch energy is wasted when the bucket of water is brought