Chapter 26 Relativity CHAPTER 26 Conceptual Questions C1 A spaceship is moving away from an observer at relativistic speed Its length at rest is 100 m but the observer measures its length as 50 m A time interval of 100 s on the spaceship would be measured by the observer to be which of the following a 50 s b 100 s c 150 s d 200 s C2 A spaceship which has length 50 m and width 10 m when at rest is moving in a direction along its length at a speed where its length contraction results in a 40 m length measured by a stationary observer What would the measured width be in this case a between 12 and 13 m b 10 m c 8 m d less than 8 m C3 When one compares the relativistic kinetic energy to the classically calculated kinetic energy for a moving object at which of the speeds listed below does the classical calculation give a greater value than the relativistic calculation a 0 2 c b 0 5 c c 0 707 c d None of the above values will give such a result C4 If the nonzero momentum of a particle with mass is doubled what happens to its total energy a It also doubles b It increases more than doubling c It stays the same since total energy is a constant for a given particle d It increases but less than doubling C5 Which form of relativity applies for observers who are accelerating a Special relativity applies b General relativity applies c Both special relativity and general relativity apply d Neither applies since the observer must be in an inertial frame to use either one 189 Chapter 26 Relativity 26 2 The Speed of Light 1 Which characterizes the main result of the Michelson Morley experiment a verified the existence of ether b involved measuring the speed of sound from a moving source c detected no difference in the speed of light regardless of speed of the source relative to observer d was designed purposely to verify Einstein s theory of relativity 2 The experiment that dispelled the idea that light travels in the ether is called the a Michelson Morley experiment b Hafele and Keating experiment c Fitzgerald Kennedy experiment d twin paradox 3 The Michelson Morley experiment was designed to make use of to find the motion of the Earth relative to the luminiferous ether a sound waves b interference fringes c electromagnetic wind d none of the above 4 The significant result of the Michelson Morley experiment was that it found a the ether moved with the sun b the ether moved with the Earth c the speed of the ether wind was greater than expected d no effect 26 3 Einstein s Principle of Relativity 5 Einstein s theory of relativity is based in part on which one of the following postulates a Mass and energy are equivalent b Space and time are absolutes c Energy is conserved only in elastic collisions d Speed of light in a vacuum is same for all observers regardless of source velocity 190 Chapter 26 Relativity 6 According to a postulate of Einstein which of the following describes the nature of the laws of physics as one observes processes taking place in various inertial frames of reference a Laws are same only in inertial frames with zero velocity b Laws are same only in inertial frames moving at low velocities c Laws are same only in inertial frames moving at near speed of light d Laws are same in all inertial frames 7 I am stationary in a reference system but if my reference system is not an inertial reference system then relative to me a system that is an inertial reference system must a remain at rest b move with constant velocity c be accelerating d be none of the above 8 The speed of light is equal to a 5 28 107 miles per hour b one meter per nanosecond c one light year per year d none of the above 9 That the speed of light in a vacuum has the same value for all inertial frames is a inconsistent with the results of the Michelson Morley experiment b consistent with the results of the Michelson Morley experiment c not related to the results of the Michelson Morley experiment d not true 26 4 Consequences of Special Relativity 10 A mass is bouncing on the end of a spring with a period T when measured by a ground observer What would the period of oscillation be as measured by the same observer if the mass and spring were moving past the ground observer at a speed of 0 80 c a 0 44 T b 0 60 T c 1 0 T d 1 7 T 11 The observed relativistic length of a super rocket moving by the observer at 0 70 c will be what factor times that of the measured rocket length if it were at rest 191 Chapter 26 Relativity a 0 45 b 0 71 c 0 82 d 1 4 192 Chapter 26 Relativity 12 The relativistic effect of time dilation has been verified by which of the following a the discovery of black holes b muon experiments c twin experiments d red shift in distant galaxies 13 According to the special theory of relativity which of the following happens to the size of the time interval between two events occurring in an inertial frame of reference as the frame s velocity with respect to the observer increases a interval increases b interval decreases c interval remains constant d interval vanishes to zero when velocity equals half speed of light 14 Doubling the momentum of a a particle doubles its relativistic total energy b a particle quadruples its relativistic total energy c a photon doubles its relativistic total energy d a photon quadruples its relativistic total energy 15 According to the special theory of relativity which of the following happens to the length of an object measured in the dimension parallel to the motion of its inertial frame of reference as the velocity of this frame increases with respect to a stationary observer a length increases b length decreases c length remains constant d length vanishes to zero when velocity equals half speed of light 16 According to the special theory of relativity if a 30 year old astronaut sent on a space mission is accelerated to speeds close to that of light and then returns to earth after 20 years as measured on earth what would be his biological age upon returning a less than 50 years b 50 years c more than 50 years d exactly 100 years 193 Chapter 26 Relativity 17 The period of a pendulum is 2 0 s in a stationary inertial frame of reference What is its period when measured by an observer moving at a speed of 0 60 c with respect to the inertial frame of reference a 1 2 s b 1 6 s c 2 5 s d 3 3 s 18 The period of an oscillating weight …