PHYS-115(3) (Kaldon-16406) Name ______________________________________WMU - Winter 2001Final Exam (Sample) - 000,000 points This was a final exam I gave at GVSU.Show All Work - Feel Free To Ask QuestionsPut All Answers On Answer Sheet - Put Name On Test And Answer SheetPlease Remain In Your Seat Until 8:50am So As Not To Disturb OthersA Relatively Fast Baseball Game (40 points)1.) The pitcher throws a blistering fastball to the plate at 0.99 c. With a mighty swing, ex-basketball superstarMichael Jordan smashes the ball 125 m into right field at 0.95 c. He then runs around the bases at 0.92 c (30 mon each side of the square). The outfielder scoops up the ball and throws it back the 125 m to home plate at0.90 c. Ignoring any times to start or stop or change direction, assuming all velocities are constant and all linesare straight, we want to find out who reaches home plate first: MJ or the ball. The umpire stands behind thecatcher at home plate the entire time. (a) From the pitcher's hand to home plate, the fastball sees a distance of2.8 m. Who sees the proper length: the pitcher or the baseball? Who has the proper time? Why?(b) The umpire says that the ball took this many seconds for the ball to streak out to right field and then returnto homeplate.(c) The baseball says that it took this many seconds.(d) Mike says it took him this many seconds to run around the bases.(e) The umpire says that it took this many seconds for Mike to run around the bases. Do you think that MJ issafe? Or is he out?Physics 115 / Sample Final Winter 2001 Page 2Half a Loaf is Better Than The Other Half of a Loaf (40 points)2.) A resistor is made half of carbon (r = 60 × 10-5 W · m) and half of copper (r = 1.68 × 10-8 W · m). Find theresistance of the resistor if it is 5.00 cm (0.0500 m) long and has a diameter of 1.00 cm (0.0100 m) and ... (a) ... in one case, each material is half the length.(b) ... the other, the resistor is split in half lengthwise.(c) What would be the resistivity of the half carbon/half copper wire in part b? Does your answer depend on thediameter of the wire?A capacitor is made with its gap half filled with dielectric (glass k = 7). The capacitor is 5.00 cm × 5.00 cm(0.0500 m × 0.0500 m) with a 1.00 cm (0.0100 m) gap. Find the capacitance for the cases where the dielectricfills (d) the bottom half and (e) the left half. Hint: Try making 2 capacitors and connecting them...Physics 115 / Sample Final Winter 2001 Page 3The Atoms Family Values II (40 points) 3.) A positive helium ion consists of a single electron in orbit around a nucleus with twoprotons and two neutrons. The neutron has approximately the same mass as the proton,but has no charge. The two protons are only about 10-15 m from each other, while theelectron is about 10-10 m from the nucleus.mp = 1.67 × 10-27 kg ; me = 9.11 × 10-31 kg(a) Find FE between the nucleus and the electron, and also between the two protons.Indicate whether each is attractive (-) or repulsive (+).(b) Find the radius and energy for the n = 1 and n = 2 states of the electron according to the Bohr model.(c) Find the energy and wavelength of the photon for Dn = 1 ® 2. Is the photon emitted or absorbed by theelectron?(d) Bohr hypothesized that the angular momentum is quantized: L = m v rn = n h = n h/2p . Find thevelocities v1 and v2 for the n = 1 and n = 2 electrons.(e) deBroglie guessed that the electron's orbit must be an integer number of wavelengths around. Find thedeBroglie wavelengths l1 and l2 for the n = 1 and n = 2 electrons. Compare l's with the circumference of theorbits.Physics 115 / Sample Final Winter 2001 Page 4Okay, The Gloves are off now; No More Mister Nice Guy... (40 points)4.) A spherical metal conductor of radius 0.100 m is charged with a hundred billion (100,000,000,000) excesselectrons. Find (a) the charge Q on the sphere and (b) the surface charge s. Of course you remember that all thecharge on a conductor is on the surface...Area of a sphere = 4pr2 ; volume of a sphere = (4/3)pr3(c) Find the magnitude of the E-field of the sphere at its surface. Does it point in or out? E for the outside of aconducting sphere is the same as for a point charge.(d) If we zoom in real close to the surface of a sphere, it appears flat. (If you've ever been to Nebraska...) Canthe Gauss' Law solution for a flat surface give us the same answer for the E-field as the solution for a sphere?Gauss' Law gave us E = 2pks for the electric field near a thin sheet of charge, but a thick conductor has aninside with E = 0, so (trust Dr. Phil on this one), E = 4pks. Use this formula to find the magnitude of theelectric field near a flat surface with the same s as the sphere.(e) Do b and d give the same solution? Why or why not?Magnetic Field (20 points)5.) Two parallel wires carry I = 500 A each out of the paper. They are 3 m apart and 20m off the ground. (a) Find the magnetic force, rFE, between the two wires. (b) Find themagnetic field, BTOTAL, due to the two wires at a place on the ground directly below theleft wire at the point X.Star Trek vs. Gilligan's Island (20 points)Still unclear about Modern Physics, Ensign Gilligan asks Scotty about those matter-anti-matter warp engines onthe U.S.S. Enterprise. Compare (c) D-D (deuterium-deuterium) fusion with (d) matter-anti-matter annihilation.Anti-deuterium has same mass as regular deuterium, but it is made solely of anti-particles: anti-protons and anti-neutrons. The energy released is the difference in mass between the whole and the sum of the parts, convertedinto energy using E = mc2. Give answers in MeV.1 u converts to 931.5 MeV = 931.5 × 106 eV10n neutron 1.008665 amu 11H proton 1.007825 amu21H deuterium 2.014102 amu 42He helium 4.002603 amu121224HH HeEnergy+® + (Fusion)1212H H Poof Energy+®--!! (Matter +