entre Number andidate Number Surname Other Names andidate Signature Genera ertificate of Education dvanced Leve Examination January 212 Physics PHY4/1 Unit 4 Fieds and Further Mechanics Section Tuesday 24 January 212 1. pm to.15 pm In addition to this paper you wi require: an objective test answer sheet a back ink or back ba-point pen a cacuator a question paper/answer book for Section (encosed) a ata and Formuae booket. Time aowed The tota time for both sections of this paper is 1 hour 45 minutes. You are advised to spend approximatey 45 minutes on this section. Instructions Use back ink or back ba-point pen. o not use penci. nswer a questions in this section. For each question there are four responses. When you have seected the response which you think is the most appropriate answer to a question, mark this response on your answer sheet. Mark a responses as instructed on your answer sheet. If you wish to change your answer to a question, foow the instructions on your answer sheet. o a rough work in this book not on the answer sheet. Information The maximum mark for this section is 25. questions in Section carry equa marks. No deductions wi be made for incorrect answers. ata and Formuae ooket is provided as a oose insert. The question paper/answer book for Section is encosed within this question paper. WMP/Jan12/PHY4/1 PHY4/1
2 o not write Mutipe choice questions Each of Questions 1 to 25 is foowed by four responses,,,, and. For each question seect the best response and mark its etter on the answer sheet. You are advised to spend approximatey 45 minutes on this section. 1 ba of mass 2. kg, initiay at rest, is acted on by a force F which varies with time t as shown by the graph. F / N 1 5 What is the veocity of the ba after 8. s? 12ms 1 14ms 1 18ms 1 16ms 1 8 t / s 4 2 body X moving with a veocity v makes an eastic coision with a stationary body Y of equa mass on a smooth horizonta surface. X m v Y m Which ine, to, in the tabe gives the veocities of the two bodies after the coision? veocity of X veocity of Y v v 2 2 v v 2 2 v v (2) WMP/Jan12/PHY4/1
o not write ba of mass m, which is fixed to the end of a ight string of ength, is reeased from rest at X. It swings in a circuar path, passing through the owest point Y at speed v. X If the tension in the string at Y is T, which one of the foowing equations represents a correct appication of Newton s aws of motion to the ba at Y? T = mv 2 mg mg T = mv 2 T mg = mv 2 T + mv 2 = mg 4 disc of diameter is turning at a steady anguar speed at frequency f about an axis through its centre. object O Y disc What is the centripeta force on a sma object O of mass m on the perimeter of the disc? 2πmf 2πmf 2 2π 2 mf 2 2πmf 2 2 axis Turn over () WMP/Jan12/PHY4/1
4 o not write 5 What is the anguar speed of a car whee of diameter.4 m when the speed of the car is 18 km h 1? 175 rad s 1 15 rad s 1 27 rad s 1 54 rad s 1 6 Which one of the foowing statements is true when an object performs simpe harmonic motion about a centra point O? The acceeration is aways directed away from O. The acceeration and veocity are aways in opposite directions. The acceeration and the dispacement from O are aways in the same direction. The graph of acceeration against dispacement is a straight ine. 7 body executes simpe harmonic motion. Which one of the graphs, to, best shows the reationship between the kinetic energy, E k, of the body and its distance from the centre of osciation? E k E k distance distance E k E k distance distance 8 mechanica system is osciating at resonance with a constant ampitude. Which one of the foowing statements is not correct? The appied force prevents the ampitude from becoming too arge. The frequency of the appied force is the same as the natura frequency of osciation of the system. The tota energy of the system is constant. The ampitude of osciations depends on the amount of damping. (4) WMP/Jan12/PHY4/1
5 o not write 9 Which one of the foowing statements about Newton s aw of gravitation is correct? Newton s aw of gravitation expains the origin of gravitationa forces. why a faing sateite burns up when it enters the Earth s atmosphere. why projecties maintain a uniform horizonta speed. how various factors affect the gravitationa force between two partices. 1 If an eectron and proton are separated by a distance of 5 1 11 m, what is the approximate gravitationa force of attraction between them? 2 1 57 N 1 47 N 4 1 47 N 5 1 7 N 11 spherica panet of uniform density ρ has radius R. Which ine, to, in the tabe gives correct expressions for the mass of the panet and the gravitationa fied strength at its surface? mass of panet gravitationa fied strength at surface 4π R 2 ρ 4π GRρ 4π R ρ 4π GRρ 4π R 4π Gρ 2 ρ 4π R 4π Gρ ρ Turn over (5) WMP/Jan12/PHY4/1
6 o not write 12 The gravitationa potentia at the surface of the Earth, of radius R, is V. What is the gravitationa potentia at a point at a height R above the Earth s surface? V 4 V 2 V 2V 1 sateite is in orbit at a height h above the surface of a panet of mass M and radius R. What is the veocity of the sateite? GM (R + h) GM (R + h) R GM (R + h) GM (R + h) R 14 repusive force F acts between two positive point charges separated by a distance r. What wi be the force between them if each charge is doubed and the distance between them is haved? 16F 12F 14F 16F (6) WMP/Jan12/PHY4/1
7 o not write 15 The distance between two point charges of + 8. n and + 2. n is 6 mm. + 8. n + 2. n 6 mm t a point between the charges, on the ine joining them, the resutant eectric fied strength is zero. How far is this point from the + 8. n charge? 2 mm 25 mm 4 mm 45 mm 16 Which one of the foowing cannot be used as a unit for eectric fied strength? Jm 1 1 J 1 s 1 m 1 N 1 s 1 Jm 1 17 capacitor stores a charge of 6 μ when charged to a potentia difference (pd) of 6. V. What wi be the pd across the pates if the charge stored increases by 5%? 1. V 14.5 V 19. V 12. V Turn over (7) WMP/Jan12/PHY4/1
8 o not write 18 The graph shows the resuts of an experiment which was carried out to investigate the reationship between the charge Q stored by a capacitor and the pd V across it. V Q Which one of the foowing statements is not correct? The energy stored can be cacuated by finding the area under the ine. If a capacitor of smaer capacitance had been used the gradient of the graph woud be steeper. If Q were doubed, the energy stored woud be quadruped. The gradient of the graph is equa to the capacitance of the capacitor. 19 1 μf capacitor is fuy charged to a pd of. kv. The energy stored in the capacitor can be used to ift a oad of 5. kg through a vertica height h. What is the approximate vaue of h?. mm.9 mm. m.9 m 2 horizonta straight wire of ength. m carries a current of 2. perpendicuar to a horizonta uniform magnetic fied of fux density 5. 1 2 T. The wire foats in equiibrium in the fied. wire perpendicuar to fied 2. uniform magnetic fied What is the mass of the wire? 8. 1 4 kg.1 1 kg. 1 2 kg 8.2 1 1 kg (8) WMP/Jan12/PHY4/1
9 o not write 21 When a β partice moves at right anges through a uniform magnetic fied it experiences a force F. n α partice moves at right anges through a magnetic fied of twice the magnetic fux density with veocity one tenth the veocity of the β partice. What is the magnitude of the force on the α partice?.2 F.4 F.8 F 4. F 22 harged partices, each of mass m and charge Q, trave at a constant speed in a circe of radius r in a uniform magnetic fied of fux density. Which expression gives the frequency of rotation of a partice in the beam? Q 2πm Q m Q πm 2πQ m 2 5 turn coi of cross-sectiona area 4. 1 m 2 is paced with its pane perpendicuar to a magnetic fied of fux density 7.5 1 4 T. What is the vaue of the fux inkage for this coi?. 1 6 Wb turns 1.5 1 Wb turns.19 Wb turns 94 Wb turns Turn over (9) WMP/Jan12/PHY4/1
1 o not write 24 The output eectromotive force (emf) of a simpe ac generator can be increased by any of the four factors isted. Which one of these factors shoud not be changed if the frequency of the output is to remain unaffected when the emf is increased? the area of the coi the number of turns on the coi the speed of rotation the strength of the magnetic fied 25 Which one of the foowing woud not reduce the energy osses in a transformer? using thinner wire for the windings using a aminated core instead of a soid core using a core made from iron instead of stee using a core that aows a the fux due to the primary coi to be inked to the secondary coi EN OF QUESTIONS (1) WMP/Jan12/PHY4/1
11 There are no questions printed on this page O NOT WRITE ON THIS PGE NSWER IN THE SPES PROVIE (11) WMP/Jan12/PHY4/1
12 There are no questions printed on this page O NOT WRITE ON THIS PGE NSWER IN THE SPES PROVIE opyright 212 Q and its icensors. rights reserved. (12) WMP/Jan12/PHY4/1