IB PHYSICS Name: Period: Date: # Marks: 51 DEVIL PHYSICS BADDEST CLASS ON CAMPUS CHAPTER 6 TEST REVIEW 1. A cyclist rides around a circular track at a uniform speed. Which of the following correctly gives the net horizontal force on the cyclist at any given instant of time? Net horizontal force along direction of motion Net horizontal force normal to direction of motion A. zero zero B. zero non zero C. non zero zero D. non zero non zero 2. A particle of mass m is moving with constant speed v in uniform circular motion. What is the total work done by the centripetal force during one revolution? A. Zero B. C. 2 mv 2 mv 2 D. 2πmv 2 3. A ball moves along the inside of a horizontal semi-circular ring as shown. The diagram is a view from above. Which arrow represents the direction of the average force on the ball? Chapter 6 Test Review Updated: 16-Nov-15 Page 1 of 10
4. A car moves from X to Y along a semicircular path. The radius of the path is 250 m and the time taken to complete the trip is 50 s. Which of the following correctly shows the magnitude of the average velocity and the magnitude of the average speed? Average velocity Average speed A. 10 m s 1 10 m s 1 B. 10 m s 1 16 m s 1 C. 16 m s 1 10 m s 1 D. 16 m s 1 16 m s 1 5. An aircraft is flying at constant speed in a horizontal circle. Which of the following diagrams best illustrates the forces acting on the aircraft in the vertical plane? Chapter 6 Test Review Updated: 16-Nov-15 Page 2 of 10
6. A brick is placed on the surface of a flat horizontal disc as shown in the diagram below. The disc is rotating at constant speed about a vertical axis through its centre. The brick does not move relative to the disc. Which of the diagrams below correctly represents the horizontal force or forces acting on the brick? 7. An astronaut in orbit around Earth is said to be weightless. This is due to the fact that the A. gravitational force on the astronaut is zero. B. astronaut and the spacecraft experience the same acceleration. C. astronaut and the spacecraft experience the same gravitational force. D. gravitational field at the position of the spacecraft is zero. 8. A small sphere X of mass M is placed a distance d from a point mass. The gravitational force on sphere X is 90 N. Sphere X is removed and a second sphere Y of mass 4M is placed a distance 3d from the same point mass. The gravitational force on sphere Y is A. 480 N. B. 160 N. C. 120 N. D. 40 N. Chapter 6 Test Review Updated: 16-Nov-15 Page 3 of 10
9. A spherical planet of uniform density has three times the mass of the Earth and twice the average radius. The magnitude of the gravitational field strength at the surface of the Earth is g. What is the gravitational field strength at the surface of the planet? A. 6 g B. C. D. 2 3 3 4 3 2 g g g 10. The weight of an object of mass 1 kg at the surface of Mars is about 4 N. The radius of Mars is about half the radius of Earth. Which of the following is the best estimate of the ratio below? A. 0.1 B. 0.2 C. 5 D. 10 mass of Mars mass of Earth 11. A spacecraft is in orbit at a distance r from the centre of the Earth. The engine of the spacecraft is fired and it moves to a new orbit of radius 2r. Which of the following describes the variations in kinetic energy and total energy of the spacecraft? Kinetic energy Total energy A. decrease increase B. decrease decrease C. increase increase D. increase decrease 12. In the diagram to the right, the ratio of the distances of Y to X is 2. What is the ratio of the acceleration of Y to that of X? A. 1/4 B. 1/2 C. 2 D. 4 X Y Chapter 6 Test Review Updated: 16-Nov-15 Page 4 of 10
13. A satellite orbits the Earth in a circular orbit. The only force on the satellite is the gravitational force from the Earth. Which of the following is correct about the acceleration of the satellite? A. It is zero B. It is constant in magnitude and direction C. It is constant in magnitude but not in direction D. It is not constant in magnitude or direction 14. This question is about gravitational fields. (a) (b) Define gravitational field strength.......... The gravitational field strength at the surface of Jupiter is 25 N kg 1 and the radius of Jupiter is 7.1 10 7 m. (i) (ii) Derive an expression for the gravitational field strength at the surface of a planet in terms of its mass M, its radius R and the gravitational constant G. Use your expression in (b)(i) above to estimate the mass of Jupiter. Chapter 6 Test Review Updated: 16-Nov-15 Page 5 of 10
15. A block of mass 5.0 kg is attached to a string of length 2.0 m which is initially horizontal. The mass is then released and swings as a pendulum. The diagram shows the mass falling to the position where the string is in the vertical position m m (a) (b) (c) (d) Calculate the speed of the block when the string is in the vertical position.......... Deduce the acceleration of the block.......... Draw arrows on both blocks to represent the forces on them. For when the string is in the vertical position: (i) state and explain whether the block is in equilibrium (ii) calculate the tension in the string Chapter 6 Test Review Updated: 16-Nov-15 Page 6 of 10
16. A particle of mass m is attached to a string of length L whose other end is attached to the ceiling as shown in the diagram. The particle moves in a horizontal circle making an angle of θ with the vertical. Air resistance may be neglected. θ (a) (b) (c) Draw arrows to represent the forces on the particle. State and explain whether the block is in equilibrium.......... The linear speed of the particle is v and its angular speed is ω. Show that: (i) (ii) Chapter 6 Test Review Updated: 16-Nov-15 Page 7 of 10
(d) The length of the string is 45 cm and θ = 60º. Use the answer in (c) to evaluate: (i) the linear speed (ii) the angular speed of the particle (e) Air resistance may no longer be neglected. Suggest the effect of air resistance on: (i) the linear speed of the particle (ii) the angle the string makes with the vertical (iii) the angular speed of the particle 17. Consider two spherical bodies of mass 16M and M as shown in the diagram. d M 16M There is a point P somewhere on the line joining the masses where the gravitational field strength is zero. Chapter 6 Test Review Updated: 16-Nov-15 Page 8 of 10
(a) (b) Determine the distance of point P from the center of the bigger mass in terms of d, the centre-to-centre distance separating the two bodies................ Draw a graph to show the variation of the gravitational field strength g due to the two masses with the distance x from the centre of the larger mass. (3) (c) A small point mass m is placed at P. (i) State the force on m. (ii) The small mass m is slightly displaced to the left of P. State and explain whether the net force on the point mass will be directed to the left or to the right. Chapter 6 Test Review Updated: 16-Nov-15 Page 9 of 10
(d) Describe qualitatively the motion of the point mass after it has been displaced to the left of P............. Chapter 6 Test Review Updated: 16-Nov-15 Page 10 of 10