Question 1

State the Constancy fo the Speed of Light postulate of special relativity.

Accepted Answer

The speed of light in a vacuum

Question 2

How fast would you have to travel in order to reach a star that is 50 light-years away from Earth when you are 40 years older than you were when you left Earth? 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 3

According to Einstein's theory of general relativity, it is impossible to perform an experiment in a local environment that will enable us to decide whether we are accelerating or in a gravitational field.

Accepted Answer

A) True 
 B)False

Question 4

To what radius would the Sun have to be condensed in order for it to become a black hole? The mass of the Sun is 1.99 × 1030 kg and G = 6.67 × 10-11 Nm2/kg2.

Accepted Answer

A)  2950 m 
B)  1470 m 
C)  6.96 × 108 m 
D)  2.66 × 106 m 
E)  3.72 × 104 m 
A)  2950 m 
B)  1470 m 
C)  6.96 × 108 m 
D)  2.66 × 106 m 
E)  3.72 × 104 m

Question 5

A spaceship carrying a light clock moves at a speed of 0.960c relative to an observer on Earth. Relative to a frame of reference that is fixed with respect to Earth, how long does it take the clock on the ship to advance 1.00 s?

Accepted Answer

A)  0.960 s 
B)  1.22 s 
C)  2.59 s 
D)  3.57 s 
E)  5.83 s 
A)  0.960 s 
B)  1.22 s 
C)  2.59 s 
D)  3.57 s 
E)  5.83 s

Question 6

The principle of equivalence states that

Accepted Answer

A)  the laws of physics are the same in all inertial frames of reference. 
B)  the speed of light is the same in any frame of reference. 
C)  clocks that move relative to one another keep time at different rates. 
D)  the length of an object depends on its speed relative to a given observer. 
E)  all physical experiments conducted in a uniform gravitational field and in an accelerated frame of reference give identical results. 
A)  the laws of physics are the same in all inertial frames of reference. 
B)  the speed of light is the same in any frame of reference. 
C)  clocks that move relative to one another keep time at different rates. 
D)  the length of an object depends on its speed relative to a given observer. 
E)  all physical experiments conducted in a uniform gravitational field and in an accelerated frame of reference give identical results.

Question 7

FIGURE 29-1  
-An astronaut is resting on a bed inclined at an angle above the floor of a spaceship, as shown in Figure 29-1. From the point of view of an observer who sees the spaceship moving to the right with a speed approaching c, the angle the bed makes with the floor

Accepted Answer

A)  is greater than the angle observed by the astronaut. 
B)  is the same as the angle observed by the astronaut. 
C)  is smaller than the angle observed by the astronaut. 
D)  could be greater or smaller than the angle observed by the astronaut depending on the actual speed of the craft. 
A)  is greater than the angle observed by the astronaut. 
B)  is the same as the angle observed by the astronaut. 
C)  is smaller than the angle observed by the astronaut. 
D)  could be greater or smaller than the angle observed by the astronaut depending on the actual speed of the craft.

Question 8

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 9

A spaceship approaches Earth with a speed 0.50c. A passenger in the spaceship measures his heartbeat as 70 beats per minute. What is his heartbeat rate according to an observer that is at rest relative to Earth?

Accepted Answer

A)  61 beats per minute 
B)  65 beats per minute 
C)  69 beats per minute 
D)  73 beats per minute 
E)  75 beats per minute 
A)  61 beats per minute 
B)  65 beats per minute 
C)  69 beats per minute 
D)  73 beats per minute 
E)  75 beats per minute

Question 10

From the Earth, they see the Enterprise approaching at 0.800c and the Klingons approaching from the opposite direction at 0.900c. From the Enterprise, the crew sees the Klingon ship approaching at what speed?

Accepted Answer

Klingons a

Question 11

Einstein's theory of general relativity applies to accelerated frames of reference.

Accepted Answer

A) True 
 B)False

Question 12

A particle is moving with a certain speed. Its speed and energy are being measured with respect to Earth. When the particle's speed doubles, the energy increases by a factor of 4. What was the original speed of the particle?

Accepted Answer

A)  0.447c 
B)  0.488c 
C)  0.523c 
D)  0.648c 
E)  0.800c 
A)  0.447c 
B)  0.488c 
C)  0.523c 
D)  0.648c 
E)  0.800c

Question 13

How fast must something be traveling if its mass increases by 10%?

Accepted Answer

The answer of How fast must something be traveling if...

Question 14

FIGURE 29-1  
-An object moves in a direction parallel to its length with a velocity that approaches the velocity of light. The length of this object, as measured by a stationary observer,

Accepted Answer

A)  approaches infinity. 
B)  approaches zero. 
C)  increases slightly. 
D)  decreases slightly. 
E)  does not change. 
A)  approaches infinity. 
B)  approaches zero. 
C)  increases slightly. 
D)  decreases slightly. 
E)  does not change.

Question 15

The atomic bomb that was dropped on Nagasaki in 1945 killed 140,000 people, helping to end World War II on the next day. It released energy equivalent to that of 20,000 tons of TNT explosive. How much mass was converted to energy when this took place?
 (1000 tons ⇔ 4.3 × 1012 J) (Incidentally, modern H-bombs have energy yields 1000 times as much!)

Accepted Answer

Question 16

A satellite, initially at rest in deep space, separates into two pieces, which move away from each other. One piece has a rest mass of 190 kg and moves away with a speed 0.280c, and the second piece moves in the opposite direction with a speed 0.600c. What is the rest mass of the second piece?

Accepted Answer

A)  88.7 kg 
B)  79.6 kg 
C)  73.9 kg 
D)  68.8 kg 
E)  52.7 kg 
A)  88.7 kg 
B)  79.6 kg 
C)  73.9 kg 
D)  68.8 kg 
E)  52.7 kg

Question 17

Astronaut Sarah leaves Earth in a spaceship at a speed of 0.280c relative to Earth. Sarah's destination is a star system 12.5 light-years away (one light-year is the distance light travels in one year). According to Sarah, how far did she travel during the trip?

Accepted Answer

A)  13.0 light-years 
B)  12.5 light-years 
C)  12.0 light-years 
D)  11.5 light-years 
E)  11.0 light-years 
A)  13.0 light-years 
B)  12.5 light-years 
C)  12.0 light-years 
D)  11.5 light-years 
E)  11.0 light-years

Question 18

A spaceship, traveling at 0.560c towards a stationary enemy station, shoots a projectile towards the station with a speed of 0.100c relative to the spaceship. What is the speed of the projectile relative to the station?

Accepted Answer

A)  0.460c 
B)  0.575c 
C)  0.600c 
D)  0.625c 
E)  0.660c 
A)  0.460c 
B)  0.575c 
C)  0.600c 
D)  0.625c 
E)  0.660c

Question 19

At what speed is the mass of an electron double its rest mass?

Accepted Answer

A)  0.500c 
B)  0.650c 
C)  0.707c 
D)  0.866c 
E)  0.960c 
A)  0.500c 
B)  0.650c 
C)  0.707c 
D)  0.866c 
E)  0.960c

Question 20

At what speed, relative to the frame of the observer making the measurement, is the length of a meter stick 0.60 m?

Accepted Answer

A)  0.40c 
B)  0.60c 
C)  0.70c 
D)  0.80c 
E)  0.90c 
A)  0.40c 
B)  0.60c 
C)  0.70c 
D)  0.80c 
E)  0.90c

Exam 29: Relativity

State the Constancy fo the Speed of Light postulate of special relativity.

How fast would you have to travel in order to reach a star that is 50 light-years away from Earth when you are 40 years older than you were when you left Earth? One light-year is the distance light travels in one year.

According to Einstein's theory of general relativity, it is impossible to perform an experiment in a local environment that will enable us to decide whether we are accelerating or in a gravitational field.

To what radius would the Sun have to be condensed in order for it to become a black hole? The mass of the Sun is 1.99 × 1030 kg and G = 6.67 × 10-11 Nm2/kg2.

A spaceship carrying a light clock moves at a speed of 0.960c relative to an observer on Earth. Relative to a frame of reference that is fixed with respect to Earth, how long does it take the clock on the ship to advance 1.00 s?

The principle of equivalence states that

FIGURE 29-1 -An astronaut is resting on a bed inclined at an angle above the floor of a spaceship, as shown in Figure 29-1. From the point of view of an observer who sees the spaceship moving to the right with a speed approaching c, the angle the bed makes with the floor

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?

A spaceship approaches Earth with a speed 0.50c. A passenger in the spaceship measures his heartbeat as 70 beats per minute. What is his heartbeat rate according to an observer that is at rest relative to Earth?

From the Earth, they see the Enterprise approaching at 0.800c and the Klingons approaching from the opposite direction at 0.900c. From the Enterprise, the crew sees the Klingon ship approaching at what speed?

Einstein's theory of general relativity applies to accelerated frames of reference.

A particle is moving with a certain speed. Its speed and energy are being measured with respect to Earth. When the particle's speed doubles, the energy increases by a factor of 4. What was the original speed of the particle?

How fast must something be traveling if its mass increases by 10%?

FIGURE 29-1 -An object moves in a direction parallel to its length with a velocity that approaches the velocity of light. The length of this object, as measured by a stationary observer,

A satellite, initially at rest in deep space, separates into two pieces, which move away from each other. One piece has a rest mass of 190 kg and moves away with a speed 0.280c, and the second piece moves in the opposite direction with a speed 0.600c. What is the rest mass of the second piece?

Astronaut Sarah leaves Earth in a spaceship at a speed of 0.280c relative to Earth. Sarah's destination is a star system 12.5 light-years away (one light-year is the distance light travels in one year). According to Sarah, how far did she travel during the trip?

A spaceship, traveling at 0.560c towards a stationary enemy station, shoots a projectile towards the station with a speed of 0.100c relative to the spaceship. What is the speed of the projectile relative to the station?

At what speed is the mass of an electron double its rest mass?

At what speed, relative to the frame of the observer making the measurement, is the length of a meter stick 0.60 m?

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 Potential Energy

Electric Current and Direct-Current Circuits

Magnetism

Magnetic Flux and Faradays Law of Induction

Alternating-Current Circuits

Electromagnetic Waves

Geometrical Optics

Optical Instruments

Physical Optics: Interference and Diffraction

Quantum Physics

Atomic Physics

Nuclear Physics and Nuclear Radiation

Filters

To what radius would the Sun have to be condensed in order for it to become a black hole? The mass of the Sun is 1.99 × 10³⁰ kg and G = 6.67 × 10^-11 Nm²/kg².