PHYS 210 Final, Fall 2010

Marks: 3 A truck moving at 36 m/s passes a police car moving at 45 m/s in the opposite direction. If the frequency of the siren is 164 Hz relative to the police car, what is the frequency (in Hz) heard by an observer in the truck as the police car approaches the truck? The speed of sound in air is 343 m/s. Do not put the unit. Answer: Incorrect Correct answer: 208.58 Marks for this submission: 0/3. Marks: 3 When the temperature of a copper penny is increased by 100 °C, its diameter increases by 0.17%. The area of one of its faces increases by: Choose one answer. 0.51% x 0.27% x 0.13% x 0.17% x 0.34% y Correct Marks for this submission: 3/3. Marks: 3 A roller-coaster car has a mass of 500 kg when fully loaded with passengers. The car passes over a hill of radius 15.0 m, as shown. The force of the track on the car at the top of the hill is 2149 N. What is the car speed (in m/s) at the top of the hill? g = 9.80 m/s2. 15m %. Answer: 9.085 Correct Marks for this submission: 3/3. 4 Marks: 3 One mole of ideal gas is initially at Pp = 1 atm and Vo= 25 Liters is slowly heated so that its state moves in a straight line on a PV-diagram to a final state P = 3 atm and V = 87 L. The work done (in Kilo Joules) by the gas is: 1 atm = 10° Pa. Give your answer in Kilo-Joules. Do not put unit. Answer: 124 Correct Marks for this submission: 3/3. The diagram shows a U-tube having cross-sectional area A and partially filled with oil of density ©. A solid cylinder, which fits the tube tightly but can slide without friction, is placed in the right arm. The system reaches equilibrium. The weight of the cylinder is: Marks: 3 Choose one answer. Cannot tell, Need more information. AP(L+h)g x 2AP(L-h)g x AP(L-h)g x ALPg v Incorrect Marks for this submission: 0/3. Marks: 3 Two slits are illuminated with green light () = 540 nm). The slits are 0.05 mm apart and the distance to the screen is 1.5 m. At what distance (in mm) from the central maximum on the screen is the average intensity 50% of the intensity of the central maximum? 1 nm = 1079 meter. Choose one answer. 0.4mm x 5 2mm x imm x 4mm vy 3mm x Incorrect Marks for this submission: 0/3. A Carnot engine works between two reservoirs at temperatures of 300 K and 116 K. If the engine absorbs 100 J from the Marks: 3 hot reservoir, find the amount of work it does (in Joules): Answer: 613 Correct Marks for this submission: 3/3. Marks: 6 Marks: 3 The Figure below shows how the stream of water emerging from a faucet “necks down” as it falls. The indicated cross- sectional areas are Ag = 1.20 cm? and A = 0.35 cm?. The two levels are separated by a vertical distance 55.5 mm. What is the volume flow (in cm/s) rate from the tap? Ty ih Hint: Use the Continuity Equation and the free fall equation. Give your answer in (cm?3/s) and take g = 9.8 m/s?. Answer: Marks for this submission: 0/6. The equation of a wave, traveling along the +x axis with an amplitude of 0.02 m, a frequency of 440 Hz, and a speed of 330 m/s is given by: Choose one answer. y = 0.02 cos [880 7 x/330 - 440t] x y = 0.02 sin[880 7 (x/330 -t)] ¥ y = 0.02 sin [8807 (x/330 + t)] x y = 0.02 cos [27 (x/330 + 440t)] x y = 0.02 sin [27 (x/330 + 440t)] x lol em oee) 10 Marks: 3 A point source emits sound waves with a power output of 100 watts. What is the sound level (in dB) at a distance of 10 m? Choose one answer. ~129 dB x ~ 119 dB x ~ 109 dB y ~139dB x ~10db x @o0o0o0o0o0o Marks for this submission: 0/3. 11 Marks: 3 An object moving along the x-axis is acted upon by a force F, that varies with position as shown. How much work is done by this force as the object moves from x = 2m to x = 8m? F,(N) x(m) Choose one answer. 2 +30) ¥ 10) x +50) x 30) x +10) x Correct Marks for this submission: 3/3. 12 Marks: 3 An organ pipe open at both ends has a radius of 4.0 cm and a length of 14 m. What is the frequency (in Hz) of the third harmonic? Assume the velocity of sound is 344 m/s. Do Not put unit next to your answer. Answer: 36.86 Correct Marks for this submission: 3/3. 13 Marks: 3 A light ray whose frequency is 6.00x 1024 Hz in vacuum is incident on piece of glass (n = 1.65). The wavelength of the light after it enters the glass is (in nm): Given: 1 nm = 10°9 meters; speed of light = 3.0 x 108 m/s. Do not put unit Answer: 500 Marks for this submission: 0/3. 14 Marks: 3 Two strings are respectively 1.00 m and 2.00 m long. Which of the following wavelengths, in meters, could represent harmonics present on both strings? Choose one answer. 1.33, 1.00,0.500 x 2.00, 1.00, 0.500 y 2.00, 1.33, 1.00 x 4.00, 2.00, 1.00 x 0.800, 0.670, 0.500 x Goo00e Tmcorrectt Marks for this submission: 0/3. 15 The frictional force of the floor on a large suitcase is least when the suitcase is: Marks: 3 Choose one answer. pushed by a force parallel to the floor. x C turned on its side and pushed by a force parallel to the floor. x 5 pulled by a force directed at an angle () above the floor. / pushed by a force directed at an angle () into the floor. x dragged by a force parallel to the floor. Correct Marks for this submissio‘ 3/3. 16 Marks: 3 The figure below represents a string which has a heavy section and a light section. The mass per unit length of the heavy section is 16 times as large as the mass per unit length of the light section. When the string is under tension, the wavelength of a wave traveling in the heavy section is times the wavelength of that same wave traveling in the light section. Choose one answer. 1x 12 x way 2x 4x Correct Marks for this submission: 3/3. 17 Marks: 3 Unpolarized light is passed through three successive Polaroid filters, each with its transmission axis at 50° to the preceding filter. What percentage of light gets through? Your answer will be in percentile, i.e. a number between 0 and 100. Answer: 354 Correct Marks for this submission: 3/3.