Vertical Speed - Physics - Solved Exam Paper, Exams of Physics

Download Vertical Speed - Physics - Solved Exam Paper and more Exams Physics in PDF only on Docsity! Physics 3204 August 2005Page 1 of 19 PART I Total Value: 50% Instructions: Shade the letter of the correct answer on the computer scorable answer sheet provided. 1. What is the vertical speed component of a projectile that is launched at an angle of 20.0o to the horizontal with an initial speed of 30.0 m/s? (A) 30.0 cos 20.0o U (B) 30.0 sin 20.0o (C) (D) 2. Which best represents the velocity components of a projectile at its maximum height? (A) (B) U (C) (D) 3. A projectile is shot horizontally at 40.0 m/s from a cannon located on a cliff 155 m high. How many seconds is the projectile in the air? (A) 0.258 s U (B) 5.62 s (C) 11.0 s (D) 31.6 s 4. A ball thrown into the air has a horizontal velocity component of 12 m/s. What is the range of the ball if it lands after 3.0 s? (A) 4.0 m U (B) 36 m (C) 51 m (D) 80 m 5. An arrow is fired at 45.5 m/s from a 5.75 m high tree branch, at an angle of 60 above theo horizontal. What maximum height, above the ground, will the arrow reach? (A) 32.1 m (B) 73.4 m (C) 79.1 m U (D) 84.9 m Physics 3204 August 2005 Page 2 of 19 6. A ball is launched at a 60 angle to the horizontal. If, 3.0 s later, it lands 12 m from theo launch site, what was the magnitude of the initial velocity? (A) 2.3 m/s (B) 4.0 m/s (C) 4.6 m/s U (D) 8.0 m/s k7. What is the frictional force for a 24 kg object on a horizontal surface if : = 0.25? (A) 6.0 N (B) 24 N U (C) 59 N (D) 96 N 8. Assuming no friction, which graph best represents the horizontal displacement of a projectile? (A) (B) (C) U (D) Physics 3204 August 2005Page 5 of 19 22. In which situation would the greatest torque be exerted on the bolt? (A) F (B) F (C) F U (D) F 23. The diagram below shows a 2.0 × 10 kg truck on a 20.0 m long uniform bridge that has a3 mass of 8.0 × 10 kg. If the truck is 6.0 m from support A, what is the magnitude of the3 upward force at support B? U (A) 4.6 × 10 N3 (B) 5.9 × 10 N3 (C) 4.5 × 10 N4 (D) 8.4 × 10 N4 24. What happens to a neutral electroscope that is briefly touched with a positively charged glass rod? (A) gains electrons (B) gains protons U (C) loses electrons (D) loses protons 25. What is the electrical potential difference required to increase the energy of a 0.20 C charged particle by 7.0 J? (A) 0.028 V (B) 1.4 V (C) 3.5 V U (D) 35 V 26. A Van de Graaf generator creates an electric field about a metal sphere. A 3.0 :C charge, near the sphere, experiences a force of 5.4 x 10 N. What is the strength of the electric-4 field at the location of the charge? (A) 1.6 x 10 N/C -9 (B) 1.8 x 10 N/C -4 (C) 5.4 x 10 N/C -4 U (D) 1.8 x 10 N/C 2 Physics 3204 August 2005 Page 6 of 19 X Y (A) negative negative (B) negative positive (C) positive negative (D) positive positive 27. Which diagram shows the gravitational field lines about a spherical object? (A) U (B) (C) (D) 28. The diagram below shows electric field lines near two charged spheres, what type of charges are present on X and Y? U 29. What is the electrostatic force between two protons separated by a distance of 1.0 × 10 m?-6 (A) -9.0 × 10 N21 U (B) -2.3 × 10 N B or C since sign is irrelevant.-16 U (C) +2.3 × 10 N-16 (D) +9.0 × 10 N21 Physics 3204 August 2005Page 7 of 19 30. Two charged objects attract each other with a force, F. By what factor would the force increase if one charge is doubled, the other charge is tripled, and the distance between their centres is reduced to one quarter its original value? (A) 6 (B) 16 (C) 24 U (D) 96 31. Which graph illustrates Ohm’s Law? U (A) (B) (C) (D) 32. Given the resisitivity of copper is 1.72 × 10 S @m, what is the resistance of a 2.00 m long-8 copper extension cord that has a diameter of 2.00 × 10 m?-3 (A) 1.72 × 10 S-11 (B) 6.88 × 10 S-11 (C) 1.72 × 10 S-5 U (D) 1.10 × 10 S-2 33. An electric clothes dryer uses a 30.0 A current for 12 minutes to dry a load of clothes. This process uses 5184 kJ of energy. What is the potential difference across the dryer? (A) 12 V (B) 14 V (C) 120 V U (D) 240 V Physics 3204 August 2005 Page 10 of 19 43. If the stopping potential of a photoelectric cell is 5.60 V, what is the maximum kinetic energy of the photoelectrons emitted? (A) 2.90 × 10 J-20 U (B) 8.96 × 10 J-19 (C) 5.60 × 10 J1 (D) 3.50 × 10 J19 44. What happens to the deBroglie wavelength of an electron if its momentum is doubled? U (A) decreases by a factor of 2 (B) decreases by a factor of 4 (C) increases by a factor of 2 (D) increases by a factor of 4 45. Which property does the Compton Effect describe about photons? (A) mass U (B) momentum (C) wave properties (D) speed rates 46. What is the energy of the emitted photon when an electron drops from the third energy level to the second energy level? (A) 1.51 eV U (B) 1.89 eV (C) 2.27 eV (D) 4.91 eV 47. How many neutrons are in the nucleus of ? (A) 82 U (B) 123 (C) 205 (D) 246 48. What is missing in the nuclear decay process below? (A) photon and alpha particle (B) photon and neutrino (C) positron and alpha particle U (D) positron and neutrino 49. An isotope of krypton has a half-life of 3 minutes. If a sample of this isotope produces 1000 counts per minute in a Geiger counter, how many counts per minute are produced after 15 minutes? (A) 0 (B) 15 U (C) 30 (D) 60 Physics 3204 August 2005Page 11 of 19 50. What types of radiation are passing through the electric field in the diagram below? X Y Z (A) alpha beta gamma (B) alpha gamma beta (C) beta alpha gamma U (D) beta gamma alpha Physics 3204 August 2005 Page 12 of 19 PART II Total Value: 50% Instructions: Complete all items in this section. Your responses must be clearly presented in a well-organized manner with proper use of units, formulae and significant figures where appropriate. Value 4% 51.(a) The diagram below represents a cannon located on a 145 m high cliff. If the cannon fires a cannonball at a 25 angle below the horizontal, with an initial velocityo of 75.0 m/s, how far will the cannonball travel in the horizontal direction before it hits the ground? dy = -145 m 1V = 75.0 m/s 1xV = cos 25 x 75.0 m/s = 68 m/s 1yV = -sin 25 x 75.0 m/s = - 31.7 m/s Vertical Motion: = 62.0 m/s [down] or -62 m/s : -62.0 m/s = -31.7m m/s + -9.80 m/s x t2 -30.0 m/s = t - 9.80 m/s2 3.09 s = t Horizontal Motion: = 68 m/s x 3.09 s = 210 m The cannonball will travel 210 m in the horizontal direction before hitting the ground. Physics 3204 August 2005Page 15 of 19 Value 3% 52.(a) Using diagrams, explain how a negatively charged Van de Graaf generator can be used to induce a permanent positive charge on a neutral electroscope. 1 3% 52.(b) What is the magnitude of the net force on Q in the diagram below? 0.20 m 1 2 Q = +3.0 :C Q = + 4 :C 0.20 m 3 Q = -5.0 :C 2on1 F = (9.0 x 10 N.m /C )(3.0 x 10 C)(4.0 x 10 C) = 2.7 N 9 2 2 -6 -6 (0.2 m)2 3on1 F = (9.0 x 10 N.m /C )(3.0 x 10 C)(5.0 x 10 C) = 3.4 N 9 2 2 -6 -6 (0.2 m)2 = 2.7 N [L] + 3.4 N [S] = 4. 3 N 1The magnitude of the net force on Q is 4.3 N. Physics 3204 August 2005 Page 16 of 19 Value 3% (c) For the circuit below, calculate: 25 S 65 V 15 S 15 S (i) the total resistance; The total resistance is 33 ohms. (ii) the current through the 25 S resistor; The total current through the 25 ohm resistor is 2.0 A 3% 52.(d) A power supply is connected to a heating element in the diagram below. (i) If a total of 5.0 × 10 electrons pass any point in the heating element circuit20 in 40.0 s, calculate the current flowing from the element. Q =N x e = 5.0 x 10 x 1.60 x 10 C = 80.0 C20 -19 I = Q = 8.0 x 10 C = 2.0 A The current flowing from the element is 2.0 A1 t 40.0 s (ii) Calculate the amount of power dissipated in the circuit. P = V x I = 15 v x 2.0 A = 15 J/C x 2.0 C/s = 30 J/s = 30 W The power dissipated in the circuit is 30 W. Physics 3204 August 2005Page 17 of 19 Value 2% (e) Why is using a cell phone a greater risk for cancer than using a typical household telephone? The cell phone has within it an electromagnetic or radio wave transmitter. It is felt that prolonged exposure to high energy electromagnetic waves can cause cell damage which is related to cancer. 3% 52.(f) An electron travels in a path perpendicular to a 1.00 × 10 T magnetic field. If the-3 radius of the circular path is 2.0 cm, how fast must the electron be traveling? mag centripetalF = F q v B=mv 2 r q v B= mv q B = m v2 r r v = q B r = (1.6 x10 C)(1.00 x10 T)(2.0 x10 m)-19 -3 -2 m 9.11 x 10 kg-31 v = 3.5 x 10 m/s6 The electron is traveling 3.5 x 10 m/s.6 3% (g) An oil drop with a mass of 9.80 × 10 kg is suspended between two horizontal-16 parallel charged plates. If the electric field strength is 2.0 × 10 N/C, how many4 electrons are on the oil drop? oil drop upward downward Force = Force e gravF = F electric gravForce = Force . 2.0 x10 N/C x q = 9.80 x 10 kg x 9.80 N/kg 4 -16 q = 4.8 x 10 C-19 N = q = 4.8 x 10 C = 3 electrons-19 e 1.6 x 10 C/e-19 There are 3 electrons on the oil drop.