UNIVERSITY OF SASKATCHEWAN Department of Physics and Engineering Physics

Transcription

1 UNIVERSITY OF SASKATCHEWAN Departent of Physics and Engineering Physics 05 Saskatchewan High School Physics Scholarship Copetition May, 05 Tie allowed: 90 inutes This copetition is based on the Saskatchewan High School Physics Curriculu. INSTRUCTIONS:. You should have a test paper and an OMR (Optical Machine Readable) or Coputer scan sheet. The test paper consists of 9 pages, including this cover page. The student should check that the test paper is coplete.. Enter your nae and school on the OMR sheet.. Enter your personal inforation on the table below.. At the end of the exaination only this cover page and the OMR sheet ust be subitted. 5. All questions are of equal value. 6. Marks are awarded for correct answers only. No arks will be deducted for wrong answers. 7. Calculators ay not be used. (None of the questions require the use of a calculator.) PEASE PRINT THE FOOWING INFORMATION Nae: School: Physics Teacher: Hoe Address: Postal Code: Telephone: Eail address: Page of 9

2 May, 05; Page FOR EACH OF THE FOOWING QUESTIONS ENTER THE MOST APPROPRIATE RESPONSE ON THE OMR SHEET. Note: In all the questions the sybol g denotes the agnitude of the acceleration due to gravity on the Earth s surface.. To deterine the area of a rectangular field I easured the width to be.6 and the length to be I find the area by ultiplying the width by length and y calculator display reads What is the best way to write y answer in scientific notation with the correct nuber of significant figures? Which one of the following stateents is correct? Heat and teperature are really the sae thing. In principle there is no lower liit for the teperature one could reach, provided a sufficiently good refrigerator could be built. Absolute zero refers to the teperature of a water-ice ixture in equilibriu on the Celsius scale. If the average kinetic energy of the olecules in a substance increases, that eans the teperature of the substance increases. Heat is easured in the sae units as a force.. Consider two solid objects which have different asses and are ade of different aterials. The aount of heat required to raise the teperature of each by 0 C will be greater for the ore assive object. be greater for the less assive object. be the sae for both objects. possibly be greater for either object depending on what they are ade of.. Heat is added at a constant rate to an object that was a solid at tie t = 0. The teperature of the object is recorded as a function of tie and is plotted on the graph. Which stateent is true? At tie 0 inutes the substance was a ixture of liquid and gas. At tie 0 inutes the substance was all gas. At tie 0 inutes the substance was a ixture of solid and liquid. At tie 0 inutes the substance was all solid. At tie 0 inutes the substance was a ixture of liquid and gas. Teperature Tie (inutes) Page of 9

3 May, 05; Page 5. Consider a transverse wave in a string that is caused by soeone wiggling the end of the string back and forth. Which one of the following options describes the quantity or quantities that deterine the speed of the wave along the string? The aplitude of the wiggling. The frequency of the wiggling. The period of the wiggling (i.e. the tie for one wiggle). The ass per unit length of the string and the tension of the string. 6. Consider the superposition of two waves with identical aplitudes and identical wavelengths, travelling along a string. The aplitude of each wave is A. At a particular instant in tie what is the aplitude of the resultant wave? It is A. It is A. It is ½ A. It can be anywhere between ½ A and A. It can be anywhere between zero and A. 7. A guitar string of length is fixed at both ends. The string is ade to vibrate at a frequency such that there are nodes in the string (not counting the nodes at the fixed ends). What is the wavelength of the wave in the string? 8. When light passes fro air into water what changes occur? The speed of the light decreases and its wavelength decreases. The speed of the light decreases and its frequency increases. The speed of the light increases and its wavelength increases. The frequency of the light decreases and its wavelength increases. The frequency of the light increases and its wavelength decreases. 9. A light ray hits the interface between air and glass at an angle of incidence as shown. Which stateent is correct? The angle of reflection is less than the angle of incidence. The angle of refraction is less than the angle of incidence. The angle of refraction is greater than the angle of incidence. The angle of refraction is equal to the angle of incidence. The angle of refraction is equal to the angle of reflection. Page of 9 Air Glass

4 May, 05; Page 0. Consider the iage fored by a convex spherical irror when the object is placed at a distance in front of the irror equal to the agnitude of the focal length of the irror. Which stateent is correct? The iage is an infinite distance away. The iage is virtual, upright and saller than the object. The iage is real, inverted and saller than the object. The iage is virtual, inverted and larger than the object. The iage is real, upright and larger than the object.. The diagra shows four rays drawn fro the head of the object arrow through a thin converging lens to locate its iage. The points labelled F are the focal points of the lens. Are any of the rays drawn incorrectly? Ray A is drawn incorrectly. Ray B is drawn incorrectly. Ray C is drawn incorrectly. Ray D is drawn incorrectly. All four rays are drawn correctly. Iage F Object F A B C D. If you were to inhale a few breaths of heliu gas, you would probably experience an ausing change in your voice. You would sound like a relative of Donald Duck or Alvin the chipunk. What is the cause of this curious effect? The heliu causes your vocal cords to tighten and vibrate at a higher frequency. For a given frequency of vibration in the gas in your throat, the wavelength of the sound is less in heliu than it is in air. Your vocal cords are resonating in their second haronic, rather than at their fundaental frequency. ow frequencies are absorbed by the heliu gas, leaving only the high frequency coponents. Sound travels faster in heliu than in air, so the sae wavelength sound will have a higher frequency.. You hear that the horn on a car eits a sound with a certain frequency and wavelength when you are standing still and the car is stationary. ater, you are standing still and the car is oving toward you when the horn is sounded. What has happened to the sound reaching your ear, copared to when the car was stationary? The sound you hear has a higher frequency and a longer wavelength. The sound you hear has a higher frequency and a shorter wavelength. The sound you hear has a lower frequency and a longer wavelength. The sound you hear has the sae frequency and a shorter wavelength. The sound you hear has a higher frequency and the sae wavelength. Page of 9

5 May, 05; Page 5. The particle nature of light is ost clearly deonstrated by which phenoenon? The photoelectric effect. The interference pattern in a double slit experient. The refraction of light. The Doppler effect. Dispersion of light by a pris. 5. The neutral ato of an isotope of Berylliu has electrons in orbit around the nucleus. The nucleus of this isotope has a total of 9 nucleons (neutron and protons) in it. How any neutrons does this nucleus contain? Two objects are dropped fro the top of a tall building. You ay ignore air resistance for this proble. Object A, which has a ass of kg, hits the ground seconds after it was dropped. Object B has a ass of kg. How long after object B was dropped will it take for it to hit the ground? second seconds seconds 8 seconds 6 seconds 7. The velocity of a car as a function of tie is plotted on the graph. How far did the car travel in the period of tie between t = 0 and t = 0 s? V (/s) t (s) 8. I go on a 0-k bicycle trip. I go the first 0 k at a speed of 0 k/h. I then go the reaining 0 k at a speed of 5 k/h. What was y average speed for the whole 0-k trip? 5 k/h 6 k/h 7 k/h 7.5 k/h 8 k/h Page 5 of 9

6 May, 05; Page 6 9. To figure out the depth of a ine shaft I drop a stone into it and start counting, one alligator, two alligator, three alligator, until I hear the stone hit the botto. If I know a two alligator ine shaft has a depth h, approxiately how deep is a four alligator ine shaft? h h h 8h h 0. Two balls are thrown fro the top of a building and they each eventually hit the horizontal ground below. You ay ignore air resistance. The blue ball is thrown horizontally with speed V and the red ball is thrown directly downward with the sae speed V. Just before it hits the ground the blue ball has speed V blue, and just before the red ball hits the ground it has speed V red. How do these two speeds copare? V blue will be greater than V red. V blue will be equal to V red. V blue will be saller than V red. We do not have enough inforation to decide on an answer.. A 0 kg ass and a kg ass are each acted on by the sae net force (which reains constant) for the sae period of tie. Both asses are at rest before the force is applied. The distance the 0 kg ass oves in this tie period is x, and the distance the kg ass oves in the sae tie period is x. Which stateent is correct? x x x 5 x 5 x x x 5 x x 5 x. A block of ass has been released and is sliding down a frictionless plane which is inclined at an angle to the horizontal. What is the agnitude of the net force on the block? g g cos g tan g sin zero Page 6 of 9

7 May, 05; Page 7. A box, with ass, is being pulled along a horizontal surface with a constant horizontal force of agnitude F as shown. The box oves at a constant velocity. The coefficient of kinetic friction between the box and the surface is k. What ust be the agnitude of F? F g k F g F k g F k F k F. A refrigerator is sitting on the kitchen floor. Consider the following forces present in this situation:. The weight of the refrigerator.. The force of the refrigerator pushing down on the floor.. The force of the refrigerator pulling up on the Earth.. The force of the floor pushing up on the refrigerator. Which pair of forces is an action-reaction pair in Newton s Third aw? Forces and. Forces and. Forces and. Forces and. Forces and. 5. An object, with ass kg, is at rest on a horizontal frictionless surface when a constant horizontal force of agnitude N is applied to it. If it oves 5 while the force is acting on it, how uch kinetic energy does it gain? 8 J 0 J 0 J 50 J 00 J 6. A ball, with a weight of 0 N, is dropped fro a height of. It hits the floor and rebounds to a height of. You ay ignore air resistance. How uch energy was converted to heat and sound in the collision of the ball with the ground? 0 J 0 J 0 J 5 J zero Page 7 of 9

8 May, 05; Page 8 7. A roller-coaster car, of ass, is oving with speed v at the top of a hill. When it reaches the botto of the hill, at a height h below the top, it is oving with speed v. You ay ignore frictional effects in this proble. What is the relationship between v and v? v v gh v v gh v v v gh v v gh v v gh h v 8. A rail car of ass is oving at speed V toward a pair of identical rail cars that are stationary and are coupled together as shown. When the car collides with the other two it couples to the and so the three rail cars ove together after the collision. You ay ignore friction during the collision. What is the speed of the three rail cars just after the collision? V V V V V V 9. A ping-pong ball oving toward the East collides with a stationary bowling ball. The ping-pong ball bounces back to the West and the bowling ball oves very slowly toward the East after the collision. Which object experienced the greater agnitude average force during the tie of the collision? Neither, both experience the sae agnitude average force. The ping-pong ball. The bowling ball. It is ipossible to tell without knowing the speed of the ping-pong ball and the actual asses of the two balls. 0. A car is oving around a circular track at a constant speed. At a particular instant, what is the direction of the acceleration of the car? It is in the sae direction as the car s velocity. It is opposite in direction as the car s velocity. It is toward the centre of the circular track. It is directly away fro the centre of the circular track. None of the above, the acceleration of the car is zero. Page 8 of 9

9 May, 05; Page 9. A car is oving around a circular track at a constant speed of agnitude V. The agnitude of the net force on the car is F. If the car now oves around the sae track at double the speed (V), what is the agnitude of the net force on the car? ½ F. F. F. F. F.. Two planets in a distant solar syste have different sizes and asses. Planet Yu has a radius R and a ass M. Planet Zork has a radius R and a ass M. The acceleration due to gravity on the surface of planet Yu is g Y. What would be the acceleration due to gravity on the surface of planet Zork? 9 9 END OF EXAMINATION Page 9 of 9