Question 1

If an electron in the lab has a kinetic energy equal to twice its rest energy,what is its speed in the lab?

Accepted Answer

A) 0.84c 
B) 0.87c 
C) 0.89c 
D) 0.91c 
E) 0.94c 
A) 0.84c 
B) 0.87c 
C) 0.89c 
D) 0.91c 
E) 0.94c

Question 2

During a reaction,a reactant loses 4.8 × 10-28 kg of mass.How many joules of energy are released? (c = 3.0 × 108 m/s)

Accepted Answer

A) 4.3 × 10-11 J 
B) 1.4 × 10-19 J 
C) 1.6 × 10-36 J 
D) 5.3 × 10-45 J 
A) 4.3 × 10-11 J 
B) 1.4 × 10-19 J 
C) 1.6 × 10-36 J 
D) 5.3 × 10-45 J

Question 3

Consider three galaxies,Alpha,Beta and Gamma.An astronomer in Beta sees each of the other two galaxies moving away from him in opposite directions at 0.70c.At what speed would an observer in Alpha see the galaxy Gamma moving?

Accepted Answer

A) 0.70c 
B) 1.4c 
C) 0.82c 
D) 0.94c 
E) 0.98c 
A) 0.70c 
B) 1.4c 
C) 0.82c 
D) 0.94c 
E) 0.98c

Question 4

A particle in a 799=m-long linear particle accelerator is moving at  
How long does the particle accelerator appear to the particle?

Accepted Answer

A) 387 m 
B) 1,039 m 
C) 184 m 
D) 1,651 m 
A) 387 m 
B) 1,039 m 
C) 184 m 
D) 1,651 m

Question 5

Astronaut Hans leaves Earth in a spaceship traveling at a speed of 0.280c relative to the observer Brian at rest on Earth.Hans is holding a pencil at an angle of 30° with the direction of travel,as seen by Hans.What angle does the pencil make with the direction of travel,as seen by Brian on Earth?

Accepted Answer

A) 29° 
B) 30° 
C) 31° 
D) 33° 
E) 90° 
A) 29° 
B) 30° 
C) 31° 
D) 33° 
E) 90°

Question 6

You are a passenger on a spaceship.As the speed of the spaceship increases,you will observe

Accepted Answer

A) your watch slowing down. 
B) your watch speeding up. 
C) your watch losing time. 
D) your watch gaining time. 
E) nothing unusual about the behavior of your watch. 
A) your watch slowing down. 
B) your watch speeding up. 
C) your watch losing time. 
D) your watch gaining time. 
E) nothing unusual about the behavior of your watch.

Question 7

One of Einstein's postulates in formulating the special theory of relativity was that the laws of physics are the same in reference frames that

Accepted Answer

A) accelerate. 
B) move at constant velocity with respect to an inertial frame. 
C) oscillate. 
D) are stationary,but not in moving frames. 
A) accelerate. 
B) move at constant velocity with respect to an inertial frame. 
C) oscillate. 
D) are stationary,but not in moving frames.

Question 8

At age 21,you set out for a star that is 50 light-years from Earth.How fast would your spaceship have to travel in order to reach that star when you are 61 years old? One light-year is the distance light travels in one year.

Accepted Answer

A) 0.58c 
B) 0.68c 
C) 0.78c 
D) 0.88c 
E) 0.96c 
A) 0.58c 
B) 0.68c 
C) 0.78c 
D) 0.88c 
E) 0.96c

Question 9

Consider three galaxies,Alpha,Beta and Gamma.An astronomer in Beta sees each of the other two galaxies moving away from her in opposite directions at 0.70c.At what speed would an observer in Alpha see the galaxy Beta moving?

Accepted Answer

A) 0.82c 
B) 0.70c 
C) 0.94c 
D) 0.35c 
E) 0.57c 
A) 0.82c 
B) 0.70c 
C) 0.94c 
D) 0.35c 
E) 0.57c

Question 10

During a reaction,170 µJ of energy is released.What change of mass would accompany this release? (c = 3.0 × 108 m/s)

Accepted Answer

A) 5.1 × 10-4 kg 
B) 1.5 × 10-13 kg 
C) 4.8 × 10-18 kg 
D) 1.9 × 10-21 kg 
A) 5.1 × 10-4 kg 
B) 1.5 × 10-13 kg 
C) 4.8 × 10-18 kg 
D) 1.9 × 10-21 kg

Question 11

Suppose one twin takes a ride in a spaceship traveling at a very high speed to a distant star and then back again,while the other twin remains on Earth.Compared to the twin who remained on Earth,the astronaut twin is

Accepted Answer

A) younger than the Earth-twin. 
B) the same age as the Earth-twin. 
C) older than the Earth-twin. 
D) The ages cannot be determined from the information provided. 
A) younger than the Earth-twin. 
B) the same age as the Earth-twin. 
C) older than the Earth-twin. 
D) The ages cannot be determined from the information provided.

Question 12

Two spaceships approach Earth from opposite directions.One has a speed of 0.21c and the other a speed of 0.34c,both relative to Earth.What is the speed of one spaceship relative to the other?

Accepted Answer

A) 0.51c 
B) 0.55c 
C) 0.58c 
D) 0.61c 
E) 0.64c 
A) 0.51c 
B) 0.55c 
C) 0.58c 
D) 0.61c 
E) 0.64c

Question 13

The figure shows a right-angled construction frame ABC.When measured at rest,it has dimensions as follows: AB = 18.9 m,AC = 10.0 m,and BC = 16.0 m.This frame is now given a new velocity of 0.420c,relative to Earth,in a direction parallel to AC.How long is part BC of this frame with the new velocity as measured by Earth-based engineers?

Accepted Answer

A) 16.0 m 
B) 14.0 m 
C) 12.0 m 
D) 10.0 m 
E) 18.0 m 
A) 16.0 m 
B) 14.0 m 
C) 12.0 m 
D) 10.0 m 
E) 18.0 m

Question 14

In a certain chemical reaction,8.1 × 10-19 J of energy is released per molecule formed.What is the difference in mass per molecule between the sum of the masses of the molecules of the reagents before the reaction and the mass of the molecules produced by the reaction? (c = 3.0 × 108 m/s)

Accepted Answer

A) 8.1 × 10-28 kg 
B) 2.7 × 10-27 kg 
C) 3.2 × 10-27 kg 
D) 5.4 × 10-32 kg 
E) 9.0 × 10-36 kg 
A) 8.1 × 10-28 kg 
B) 2.7 × 10-27 kg 
C) 3.2 × 10-27 kg 
D) 5.4 × 10-32 kg 
E) 9.0 × 10-36 kg

Question 15

A spaceship carrying a light clock moves at a speed of 0.960c relative to an observer on Earth.If the clock on the ship advances by 1.00 s as measured by the space travelers aboard the ship,how long did that advance take as measured by the observer on Earth?

Accepted Answer

A) 0.96 s 
B) 1.2 s 
C) 2.6 s 
D) 3.6 s 
E) 5.8 s 
A) 0.96 s 
B) 1.2 s 
C) 2.6 s 
D) 3.6 s 
E) 5.8 s

Question 16

How many MeV of energy is released during a reaction in which 1.67 × 10-25 kg of material is converted to energy? (c = 3.0 × 108 m/s,1 eV = 1.67 × 10-19 J)

Accepted Answer

A) 5.0 × 10-14 MeV 
B) 4.1 × 10-7 MeV 
C) 3.1 × 10-4 MeV 
D) 9.4 × 104 MeV 
A) 5.0 × 10-14 MeV 
B) 4.1 × 10-7 MeV 
C) 3.1 × 10-4 MeV 
D) 9.4 × 104 MeV

Question 17

A spaceship with a constant speed of 0.800c relative to Earth travels to a star that is 4.30 light-years from Earth.How much time for this trip would elapse on a clock on board the spaceship?

Accepted Answer

A) 3.23 y 
B) 4.40 y 
C) 5.15 y 
D) 5.38 y 
A) 3.23 y 
B) 4.40 y 
C) 5.15 y 
D) 5.38 y

Question 18

You are a passenger on a spaceship.As the speed of the spaceship increases,you will observe

Accepted Answer

A) the length of your spaceship getting shorter. 
B) the length of your spaceship getting longer. 
C) the length of your spaceship is zero. 
D) no change in the length of your spaceship. 
A) the length of your spaceship getting shorter. 
B) the length of your spaceship getting longer. 
C) the length of your spaceship is zero. 
D) no change in the length of your spaceship.

Question 19

A spaceship approaching an asteroid at a speed of 0.60c launches a scout rocket with speed 0.40c relative to the spaceship.At what speed is the scout rocket approaching the asteroid?

Accepted Answer

A) 0.81c 
B) 1.0c 
C) 0.76c 
D) 0.64c 
E) 0.96c 
A) 0.81c 
B) 1.0c 
C) 0.76c 
D) 0.64c 
E) 0.96c

Question 20

Astronaut Rachel leaves Earth in a spaceship at a speed of 0.960c relative to an observer on Earth.Rachel's destination is a star system 14.4 light-years away (one light-year is the distance light travels in one year).According to Rachel,how long does the trip take?

Accepted Answer

A) 14 years 
B) 15 years 
C) 11 years 
D) 4.2 years 
E) 23 years 
A) 14 years 
B) 15 years 
C) 11 years 
D) 4.2 years 
E) 23 years

Exam 29: Relativity

If an electron in the lab has a kinetic energy equal to twice its rest energy,what is its speed in the lab?

During a reaction,a reactant loses 4.8 × 10-28 kg of mass.How many joules of energy are released? (c = 3.0 × 108 m/s)

Consider three galaxies,Alpha,Beta and Gamma.An astronomer in Beta sees each of the other two galaxies moving away from him in opposite directions at 0.70c.At what speed would an observer in Alpha see the galaxy Gamma moving?

A particle in a 799=m-long linear particle accelerator is moving at How long does the particle accelerator appear to the particle?

Astronaut Hans leaves Earth in a spaceship traveling at a speed of 0.280c relative to the observer Brian at rest on Earth.Hans is holding a pencil at an angle of 30° with the direction of travel,as seen by Hans.What angle does the pencil make with the direction of travel,as seen by Brian on Earth?

You are a passenger on a spaceship.As the speed of the spaceship increases,you will observe

One of Einstein's postulates in formulating the special theory of relativity was that the laws of physics are the same in reference frames that

At age 21,you set out for a star that is 50 light-years from Earth.How fast would your spaceship have to travel in order to reach that star when you are 61 years old? One light-year is the distance light travels in one year.

Consider three galaxies,Alpha,Beta and Gamma.An astronomer in Beta sees each of the other two galaxies moving away from her in opposite directions at 0.70c.At what speed would an observer in Alpha see the galaxy Beta moving?

During a reaction,170 µJ of energy is released.What change of mass would accompany this release? (c = 3.0 × 108 m/s)

Suppose one twin takes a ride in a spaceship traveling at a very high speed to a distant star and then back again,while the other twin remains on Earth.Compared to the twin who remained on Earth,the astronaut twin is

Two spaceships approach Earth from opposite directions.One has a speed of 0.21c and the other a speed of 0.34c,both relative to Earth.What is the speed of one spaceship relative to the other?

In a certain chemical reaction,8.1 × 10-19 J of energy is released per molecule formed.What is the difference in mass per molecule between the sum of the masses of the molecules of the reagents before the reaction and the mass of the molecules produced by the reaction? (c = 3.0 × 108 m/s)

A spaceship carrying a light clock moves at a speed of 0.960c relative to an observer on Earth.If the clock on the ship advances by 1.00 s as measured by the space travelers aboard the ship,how long did that advance take as measured by the observer on Earth?

How many MeV of energy is released during a reaction in which 1.67 × 10-25 kg of material is converted to energy? (c = 3.0 × 108 m/s,1 eV = 1.67 × 10-19 J)

A spaceship with a constant speed of 0.800c relative to Earth travels to a star that is 4.30 light-years from Earth.How much time for this trip would elapse on a clock on board the spaceship?

You are a passenger on a spaceship.As the speed of the spaceship increases,you will observe

A spaceship approaching an asteroid at a speed of 0.60c launches a scout rocket with speed 0.40c relative to the spaceship.At what speed is the scout rocket approaching the asteroid?

Astronaut Rachel leaves Earth in a spaceship at a speed of 0.960c relative to an observer on Earth.Rachel's destination is a star system 14.4 light-years away (one light-year is the distance light travels in one year).According to Rachel,how long does the trip take?

Introduction to Physics

One-Dimensional Kinematics

Vectors in Physics

Two-Dimensional Kinematics

Newtons Laws of Motion

Applications of Newtons Laws

Work and Kinetic Energy

Potential Energy and Conservation of Energy

Linear Momentum and Collisions

Rotational Kinematics and Energy

Rotational Dynamics and Static Equilibrium

Gravity

Oscillations About Equilibrium

Waves and Sound

Fluids

Temperature and Heat

Phases and Phase Changes

The Laws of Thermodynamics

Electric Charges, Forces, and Fields

Electric Potential and Electric

Electric Current and Direct-Current Circuits

Magnetism

Magnetic Flux and Faradays Law of Induction

Alternating-Current Circuits

Electromagnetic Waves

Geometrical Optics

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Physical Optics: Interference and Diffraction

Quantum Physics

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During a reaction,a reactant loses 4.8 × 10^-28 kg of mass.How many joules of energy are released? (c = 3.0 × 10⁸ m/s)

During a reaction,170 µJ of energy is released.What change of mass would accompany this release? (c = 3.0 × 10⁸ m/s)

In a certain chemical reaction,8.1 × 10^-19 J of energy is released per molecule formed.What is the difference in mass per molecule between the sum of the masses of the molecules of the reagents before the reaction and the mass of the molecules produced by the reaction? (c = 3.0 × 10⁸ m/s)

How many MeV of energy is released during a reaction in which 1.67 × 10^-25 kg of material is converted to energy? (c = 3.0 × 10⁸ m/s,1 eV = 1.67 × 10^-19 J)