Question 1

A pion lives 26 ns in its rest frame,but an observer in a laboratory in which the particle moves at a speed of 2.7 $\times$ 108 m/s says the particle lived

Accepted Answer

A) 11 ns 
B) 15 ns 
C) 43 ns 
D) 60 ns 
E) 79 ns 
A) 11 ns 
B) 15 ns 
C) 43 ns 
D) 60 ns 
E) 79 ns D

Question 2

You stand on a corner as a friend drives past in an automobile.You both note the time interval required for the car to travel one block,and you both measure the distance traveled.The proper time interval is measured by _____,and the proper distance is measured by _____.

Accepted Answer

A) you; you 
B) you; your friend 
C) your friend; you 
D) your friend; your friend 
E) your friend; both of you 
A) you; you 
B) you; your friend 
C) your friend; you 
D) your friend; your friend 
E) your friend; both of you C

Question 3

A standard Canadian football field is 100 m long and 60 m wide.A UFO streaks from one end of the field to the other at a speed of 0.6c relative to the players on the field.An observer in the UFO measures the width of the field to be

Accepted Answer

A) 60 m 
B) 80 m 
C) 100 m 
D) 125 m 
E) 167 m 
A) 60 m 
B) 80 m 
C) 100 m 
D) 125 m 
E) 167 m A

Question 4

In the twenty-second century,a hyperfast New York to Los Angeles train roars through St.Louis without stopping at a speed of 0.80c.The front of the train arrives at the St.Louis station at precisely 12:00 noon according to all the clocks on the train (which are all synchronized in the train's frame),and the passengers are called to lunch in the dining car.An observer on the station platform manages to catch a glimpse of a clock at the front of the train that reads exactly 12:00 noon.What is the time at this instant at the rear of the train,according to the observer on the platform,if the train is 500 m long in its rest frame?

Accepted Answer

A) 1.35 $\mu$s past noon 
B) 1.35 $\mu$s before noon 
C) noon exactly 
D) 1.35 ms past noon 
E) 1.35 ms before noon 
A) 1.35 $\mu$s past noon 
B) 1.35 $\mu$s before noon 
C) noon exactly 
D) 1.35 ms past noon 
E) 1.35 ms before noon

Question 5

A pion lives 26 ns in its rest frame.It travels 15 cm down a beam pipe in a particle accelerator before it decays into other particles.How far is this in the rest frame of the pion?

Accepted Answer

A) 19.026 cm 
B) 18.465 cm 
C) 16.123 cm 
D) 14.997 cm 
E) 12.886 cm 
A) 19.026 cm 
B) 18.465 cm 
C) 16.123 cm 
D) 14.997 cm 
E) 12.886 cm

Question 6

The mass of an electron traveling at 0.8c is how many times as great as its rest mass?

Accepted Answer

A) 0.60 
B) 0.78 
C) 0.80 
D) 1.28 
E) 1.67 
A) 0.60 
B) 0.78 
C) 0.80 
D) 1.28 
E) 1.67

Question 7

An electron has 1022 keV of kinetic energy.What is its mass?

Accepted Answer

A) 9.11 $\times$ 10-31 kg 
B) 1.82 $\times$ 10-30 kg 
C) 3.64 $\times$ 10-30 kg 
D) 4.56 $\times$ 10-31 kg 
E) 2.73 $\times$ 10-30 kg 
A) 9.11 $\times$ 10-31 kg 
B) 1.82 $\times$ 10-30 kg 
C) 3.64 $\times$ 10-30 kg 
D) 4.56 $\times$ 10-31 kg 
E) 2.73 $\times$ 10-30 kg

Question 8

Suppose the speed of light is determined experimentally to be 299,796 ± 4 km/s.If the total path length for your interferometer is exactly 11.0 m,how big an error in the time required for the light to travel through the apparatus corresponds to the uncertainty (±4 km/s)in the speed of light?

Accepted Answer

A) 4.9 $\times$ 10-13 s 
B) 2.7 $\times$ 10-3 s 
C) 3.7 $\times$ 10-8 s 
D) 4.9 $\times$ 10-10 s 
E) 9.2 $\times$ 10-12 s 
A) 4.9 $\times$ 10-13 s 
B) 2.7 $\times$ 10-3 s 
C) 3.7 $\times$ 10-8 s 
D) 4.9 $\times$ 10-10 s 
E) 9.2 $\times$ 10-12 s

Question 9

When a particle of rest mass mo undergoes an increase in its velocity,

Accepted Answer

A) only its mass increases. 
B) only its kinetic energy increases. 
C) its mass decreases. 
D) its mass decreases and its kinetic energy increases. 
E) both its mass and its kinetic energy increase. 
A) only its mass increases. 
B) only its kinetic energy increases. 
C) its mass decreases. 
D) its mass decreases and its kinetic energy increases. 
E) both its mass and its kinetic energy increase.

Question 10

An electron with a kinetic energy of 2 MeV is produced in a betatron.Its momentum is approximately

Accepted Answer

A) 8.2 $\times$ 10-3 kg · m/s 
B) 1.31 $\times$ 10-27 kg · m/s 
C) 7.63 $\times$ 10-22 kg · m/s 
D) 1.31 $\times$ 10-21 kg · m/s 
E) 7.63 $\times$ 10-25 kg · m/s 
A) 8.2 $\times$ 10-3 kg · m/s 
B) 1.31 $\times$ 10-27 kg · m/s 
C) 7.63 $\times$ 10-22 kg · m/s 
D) 1.31 $\times$ 10-21 kg · m/s 
E) 7.63 $\times$ 10-25 kg · m/s

Question 11

A clock has a period of exactly 1 second when at rest.If you were to measure a period of 1.5 seconds for the same clock,how fast is it moving relative to you as a percentage of the speed of light?

Accepted Answer

A) 44% 
B) 31% 
C) 67% 
D) 75% 
E) 87% 
A) 44% 
B) 31% 
C) 67% 
D) 75% 
E) 87%

Question 12

What is the momentum of a photon having the same total energy as an electron with a kinetic energy of 100 keV?

Accepted Answer

A) zero 
B) 611 keV/c 
C) 100 keV/c 
D) 211 keV/c 
E) 411 keV/c 
A) zero 
B) 611 keV/c 
C) 100 keV/c 
D) 211 keV/c 
E) 411 keV/c

Question 13

You see a system consisting of a mass oscillating on the end of a spring passed you at a speed u and note that the period of the system is T.Your strange friend,who is moving with the mass-spring system,also measures its period and finds a period that is

Accepted Answer

A) equal to T. 
B) less than T. 
C) greater than T. 
D) either a or b depending on whether the system was approaching or receding from the first observer. 
E) There is not sufficient information to answer the question. 
A) equal to T. 
B) less than T. 
C) greater than T. 
D) either a or b depending on whether the system was approaching or receding from the first observer. 
E) There is not sufficient information to answer the question.

Question 14

A particle accelerator collides beams of protons and anti-protons with equal and opposite momenta.The aim of an experiment is to create a possible new massive particle with neutral charge and a mass 6 times that of a single proton.Calculate the necessary speed of the protons (and anti-protons)in the collision as a % of the speed of light.

Accepted Answer

A) 85.9% c 
B) 99.9% c 
C) 98.7% c 
D) 94.3% c 
E) None of these is correct. 
A) 85.9% c 
B) 99.9% c 
C) 98.7% c 
D) 94.3% c 
E) None of these is correct.

Question 15

At what speed would an electron's mass be measured as 4 times its rest mass?

Accepted Answer

A) 0.88c 
B) 0.97c 
C) 0.94c 
D) 0.25c 
E) 0.063c 
A) 0.88c 
B) 0.97c 
C) 0.94c 
D) 0.25c 
E) 0.063c

Question 16

An astronaut aboard a spacecraft enroute to Mars with a speed of 0.5c relative to Earth observes a meteor approaching head on at a speed of 0.9c.What is the speed of the meteor relative to Earth?

Accepted Answer

A) 1.4c 
B) -0.73c 
C) 0.4c 
D) 2.55c 
E) None of these is correct. 
A) 1.4c 
B) -0.73c 
C) 0.4c 
D) 2.55c 
E) None of these is correct.

Question 17

An earthbound radar monitors a spaceship moving at 0.9c that is being followed by a second ship moving at 0.8c.The second ship records the velocity of the faster ship as

Accepted Answer

A) 0.080c 
B) 0.10c 
C) 0.72c 
D) 0.36c 
E) 1.7c 
A) 0.080c 
B) 0.10c 
C) 0.72c 
D) 0.36c 
E) 1.7c

Question 18

A standard Canadian football field is 100 m long and 60 m wide.A UFO streaks from one end of the field to the other at a speed of 0.6c relative to the players on the field.The aliens in the UFO decide to watch the game on television as they head off toward Jupiter.The game begins at 1:30 p.m.and ends at 4:30 p.m.according to earthbound broadcasters.The elapsed time for the game according to the aliens is

Accepted Answer

A) 1.8 h 
B) 2.4 h 
C) 3.0 h 
D) 3.8 h 
E) 5.0 h 
A) 1.8 h 
B) 2.4 h 
C) 3.0 h 
D) 3.8 h 
E) 5.0 h

Question 19

While astronauts in a spaceship with a speed of 0.6c relative to Earth move outward from Earth toward Jupiter,they observe a cosmic ray shower that contains protons moving toward them.On Earth the speed of these protons is measured as 0.2c toward the spaceship.They measure the speed of the protons to be

Accepted Answer

A) 0.80c 
B) 0.71c 
C) 0.95c 
D) 0.69c 
E) 0.45c 
A) 0.80c 
B) 0.71c 
C) 0.95c 
D) 0.69c 
E) 0.45c

Question 20

Use the following scenario for the next three questions.
A 26-year-old biologist makes a trip to study alien life forms in a distant planet 10 light-years away.The round trip including a stay of 1 year in the distance planet takes 21.5 years according to the clock on earth.The biologist's son is 3-year-old when he left.Assume that the planet is not moving with respect to Earth,and the speed is the same for both outbound and inbound part of the journey.
-How fast is the spaceship traveling?

Accepted Answer

A) 0.375c 
B) 0.5c 
C) 0.67c 
D) 0.845c 
E) 0.976c 
A) 0.375c 
B) 0.5c 
C) 0.67c 
D) 0.845c 
E) 0.976c

Exam 39: Relativity

A pion lives 26 ns in its rest frame,but an observer in a laboratory in which the particle moves at a speed of 2.7 ×\times× 108 m/s says the particle lived

You stand on a corner as a friend drives past in an automobile.You both note the time interval required for the car to travel one block,and you both measure the distance traveled.The proper time interval is measured by _____,and the proper distance is measured by _____.

A standard Canadian football field is 100 m long and 60 m wide.A UFO streaks from one end of the field to the other at a speed of 0.6c relative to the players on the field.An observer in the UFO measures the width of the field to be

A pion lives 26 ns in its rest frame.It travels 15 cm down a beam pipe in a particle accelerator before it decays into other particles.How far is this in the rest frame of the pion?

The mass of an electron traveling at 0.8c is how many times as great as its rest mass?

An electron has 1022 keV of kinetic energy.What is its mass?

Suppose the speed of light is determined experimentally to be 299,796 ± 4 km/s.If the total path length for your interferometer is exactly 11.0 m,how big an error in the time required for the light to travel through the apparatus corresponds to the uncertainty (±4 km/s)in the speed of light?

When a particle of rest mass mo undergoes an increase in its velocity,

An electron with a kinetic energy of 2 MeV is produced in a betatron.Its momentum is approximately

A clock has a period of exactly 1 second when at rest.If you were to measure a period of 1.5 seconds for the same clock,how fast is it moving relative to you as a percentage of the speed of light?

What is the momentum of a photon having the same total energy as an electron with a kinetic energy of 100 keV?

You see a system consisting of a mass oscillating on the end of a spring passed you at a speed u and note that the period of the system is T.Your strange friend,who is moving with the mass-spring system,also measures its period and finds a period that is

At what speed would an electron's mass be measured as 4 times its rest mass?

An astronaut aboard a spacecraft enroute to Mars with a speed of 0.5c relative to Earth observes a meteor approaching head on at a speed of 0.9c.What is the speed of the meteor relative to Earth?

An earthbound radar monitors a spaceship moving at 0.9c that is being followed by a second ship moving at 0.8c.The second ship records the velocity of the faster ship as

Systems of Measurement

Motion in One Dimension

Motion in Two and Three Dimensions

Newtons Laws

Applications of Newtons Laws

Work and Energy

Conservation of Energy

Systems of Particles and Conservation of Linear Momentum

Rotation

Conservation of Angular Momentum

Gravity

Static Equilibrium and Elasticity

Fluids

Oscillations

Wave Motion

Superposition and Standing Waves

Temperature and the Kinetic Theory of Gases

Heat and the First Law of Thermodynamics

The Second Law of Thermodynamics

Thermal Properties and Processes

The Electric Field I: Discrete Charge Distributions

The Electric Field Ii: Continuous Charge Distributions

Electric Potential

Capacitance

Electric Current and Direct-Current Circuits

The Magnetic Field

Sources of the Magnetic Field

Magnetic Induction

Alternating-Current Circuits

Maxwells Equations and Electromagnetic Waves

Properties of Light

Optical Images

Interference and Diffraction

Wave Particle Duality and Quantum Physics

Applications of the Schrodinger Equation

Atoms

Molecules

Solids and the Theory of Conduction

Nuclear Physics

Elementary Particles and the Beginning of the Universe

Filters

A pion lives 26 ns in its rest frame,but an observer in a laboratory in which the particle moves at a speed of 2.7 $\times$ 10⁸ m/s says the particle lived

You stand on a corner as a friend drives past in an automobile.You both note the time interval required for the car to travel one block,and you both measure the distance traveled.The proper time interval is measured by _,and the proper distance is measured by _.

When a particle of rest mass m_o undergoes an increase in its velocity,