Question 1

An object has a weight of 100 N on the surface of the Earth. If the object is moved to 2RE above the surface of the Earth, its weight is

Accepted Answer

A)  25.0 N. 
B)  11.0 N. 
C)  0 N. 
D)  100 N. 
A)  25.0 N. 
B)  11.0 N. 
C)  0 N. 
D)  100 N. B

Question 2

The mass of Mars is 6.42 $\times$ 1023 kg, and the radius of the planet is 3.40 $\times$ 106 m. The acceleration due to gravity on the surface of Mars is

Accepted Answer

A)  3.7 cm/s2. 
B)  37 cm/s2. 
C)  370 cm/s2. 
D)  37 m/s2. 
A)  3.7 cm/s2. 
B)  37 cm/s2. 
C)  370 cm/s2. 
D)  37 m/s2. C

Question 3

The Earth's radius is 6.4 $\times$ 106 m. The acceleration due to gravity (in g's) that is experienced by an object at a distance of 150 miles (240 km) above the Earth's surface is

Accepted Answer

A)  zero because the object is in space (0 g). 
B)  0.51 g. 
C)  1.0 g. 
D)  0.92 g. 
A)  zero because the object is in space (0 g). 
B)  0.51 g. 
C)  1.0 g. 
D)  0.92 g. D

Question 4

Low Earth orbit (LEO) is approximately 150 miles (240 km) above the surface of the Earth. The radius and mass of the Earth are 6.4 $\times$ 106 m and 5.98 $\times$ 1024 kg. The escape velocity of an object in LEO is

Accepted Answer

A)  10 km/s. 
B)  11 km/s. 
C)  2.0 $\times$ 102 m/s. 
D)  unknown; we cannot determine the answer without knowing the mass of the object. 
A)  10 km/s. 
B)  11 km/s. 
C)  2.0 $\times$ 102 m/s. 
D)  unknown; we cannot determine the answer without knowing the mass of the object.

Question 5

The gravitational potential energy of a planet orbiting around a star is U0 when the distance between the two objects is r0. If the distance between the planet and the star is increased to 2r0, the gravitational potential energy is

Accepted Answer

A)  U0/4. 
B)  U0/2. 
C)  2U0. 
D)  4U0. 
A)  U0/4. 
B)  U0/2. 
C)  2U0. 
D)  4U0.

Question 6

Two masses, M1 = 1022 kg and M2 = 1030 kg, are separated by a distance of 1011 m. The magnitude of the gravitational force between the two masses is

Accepted Answer

A)  1020 N. 
B)  1031 N. 
C)  1028 N. 
D)  1022 N. 
A)  1020 N. 
B)  1031 N. 
C)  1028 N. 
D)  1022 N.

Question 7

In metric units, the dimensions of the gravitational constant G are

Accepted Answer

A)  [newton]·[meters] / [kilogram]. 
B)  [newton]·[meters] / [kilogram2]. 
C)  [newton]·[meters2] / [kilogram]. 
D)  [newton]·[meters2] / [kilogram2]. 
A)  [newton]·[meters] / [kilogram]. 
B)  [newton]·[meters] / [kilogram2]. 
C)  [newton]·[meters2] / [kilogram]. 
D)  [newton]·[meters2] / [kilogram2].

Question 8

Ignoring friction, the path of a projectile launched at a speed greater than the escape velocity at a planet's surface is

Accepted Answer

A)  a circle. 
B)  an ellipse. 
C)  a hyperbola. 
D)  a parabola. 
A)  a circle. 
B)  an ellipse. 
C)  a hyperbola. 
D)  a parabola.

Question 9

The gravitational force on a satellite in a highly elliptical orbit, after it passes the point of closest approach to the Earth and before it reaches the point of farthest separation from the Earth, has a component

Accepted Answer

A)  in the same direction as the velocity of the satellite. 
B)  in the direction opposite to the velocity of the satellite. 
C)  Either of the previous answers is correct. 
D)  Neither of the previous answers is correct. 
A)  in the same direction as the velocity of the satellite. 
B)  in the direction opposite to the velocity of the satellite. 
C)  Either of the previous answers is correct. 
D)  Neither of the previous answers is correct.

Question 10

Atomic oxygen is one of the major constituents of the upper atmosphere in the region of low Earth orbit (LEO). LEO is approximately 150 miles $( 240 \mathrm {~km} )$ above the surface of the Earth. The radius and mass of the Earth are $6.4 \times 10 ^ { 6 } \mathrm {~m}$ and $5.98 \times 10 ^ { 24 } \mathrm {~kg}$. The mass of atomic oxygen is $16 \times \left( 1.67 \times 10 ^ { - 27 } \mathrm {~kg} \right)$. The kinetic energy at which the atomic oxygen strikes the surface of the space shuttle is

Accepted Answer

A)  8.0 $\times$ 10-18 J. 
B)  8.0 $\times$ 10-19 J. 
C)  8.0 $\times$ 10-20 J. 
D)  8.0 $\times$ 10-21 J. 
A)  8.0 $\times$ 10-18 J. 
B)  8.0 $\times$ 10-19 J. 
C)  8.0 $\times$ 10-20 J. 
D)  8.0 $\times$ 10-21 J.

Question 11

The orbit of Io, a moon of Jupiter, is found to have a period of 1.769 days, and its average distance from the center of Jupiter is 420,000 km. The mass of Jupiter

Accepted Answer

A)  is 1.9 $\times$ 1027 kg. 
B)  is 2.2 $\times$ 1037 kg. 
C)  is 8.0 $\times$ 1027 kg. 
D)  cannot be determined without knowing the mass of Io. 
A)  is 1.9 $\times$ 1027 kg. 
B)  is 2.2 $\times$ 1037 kg. 
C)  is 8.0 $\times$ 1027 kg. 
D)  cannot be determined without knowing the mass of Io.

Question 12

Kepler's Third Law, where k is a proportionality constant, is

Accepted Answer

A)  T2 = kr3. 
B)  T2 = kr. 
C)  T2 = kr2. 
D)  T = kr3 . 
A)  T2 = kr3. 
B)  T2 = kr. 
C)  T2 = kr2. 
D)  T = kr3 .

Question 13

An asteroid has a mass of approximately 1015 kg and a diameter of 10 km. The escape velocity for an object at the surface of the asteroid is

Accepted Answer

A)  7.1 $\times$ 102 m/s. 
B)  27 m/s. 
C)  3.6 $\times$ 102 m/s. 
D)  19 m/s. 
A)  7.1 $\times$ 102 m/s. 
B)  27 m/s. 
C)  3.6 $\times$ 102 m/s. 
D)  19 m/s.

Question 14

The radius and mass of the Earth are 6.4 $\times$ 106 m and 5.98 $\times$ 1024 kg. Assume that a meteor starts at infinity with zero velocity and is attracted to the Earth. Neglecting friction, the speed at which it will strike the Earth is

Accepted Answer

A)  36 km/h. 
B)  11 km/h. 
C)  100 km/h. 
D)  unknown; we cannot determine the answer without knowing the mass of the object. 
A)  36 km/h. 
B)  11 km/h. 
C)  100 km/h. 
D)  unknown; we cannot determine the answer without knowing the mass of the object.

Question 15

A planet in another solar system is found to have twice the radius of the Earth and a mass that is double that of the Earth. The acceleration due to gravity on this other planet is

Accepted Answer

A)  0.50 g. 
B)  1.0 g. 
C)  1.5 g. 
D)  2.0 g. 
A)  0.50 g. 
B)  1.0 g. 
C)  1.5 g. 
D)  2.0 g.

Question 16

The gravitational potential energy U for an orbiting body depends on the distance r between it and the orbited body as

Accepted Answer

A)  r+1. 
B)  r+2. 
C)  r-1. 
D)  r-2. 
A)  r+1. 
B)  r+2. 
C)  r-1. 
D)  r-2.

Question 17

Low Earth orbit (LEO) is approximately 150 miles (240 km) above the surface of the Earth. The radius and mass of the Earth are 6.4 $\times$ 106 m and 5.98 $\times$ 1024 kg. The velocity of the space shuttle in LEO

Accepted Answer

A)  is 7.9 km/s. 
B)  is 7.7 km/s. 
C)  is 7.9 m/s. 
D)  cannot be determined without knowing the mass of the shuttle. 
A)  is 7.9 km/s. 
B)  is 7.7 km/s. 
C)  is 7.9 m/s. 
D)  cannot be determined without knowing the mass of the shuttle.

Question 18

The Moon orbits the Earth with a period of about 28 days. The two bodies are separated by a distance ~ 250,000 miles. An Earth satellite at a distance ~125,000 miles would have a period (in days) of

Accepted Answer

A)  $( 1 / \sqrt { 16 } ) \times 28$ days. 
B)  $( 1 / \sqrt { 8 } ) \times 28$ days. 
C)  $( 1 / \sqrt { 4 } ) \times 28$ days. 
D)  $( 1 / \sqrt { 2 } ) \times 28$ days. 
A)  $( 1 / \sqrt { 16 } ) \times 28$ days. 
B)  $( 1 / \sqrt { 8 } ) \times 28$ days. 
C)  $( 1 / \sqrt { 4 } ) \times 28$ days. 
D)  $( 1 / \sqrt { 2 } ) \times 28$ days.

Question 19

An Earth satellite in an elliptical orbit "speeds down" (that is, as it comes closer to the Earth, its speed increases). This is consistent with the fact that the gravitational potential energy U of the satellite-Earth system at points closer to the Earth is

Accepted Answer

A)  larger than U at points farther from the Earth. 
B)  equal to U at points farther from the Earth. 
C)  less than U at points farther from the Earth. 
D)  Hold it! None of the above responses is correct. 
A)  larger than U at points farther from the Earth. 
B)  equal to U at points farther from the Earth. 
C)  less than U at points farther from the Earth. 
D)  Hold it! None of the above responses is correct.

Question 20

The gravitational potential energy U is related to the gravitational force F by an equation of the form

Accepted Answer

A)  $U \propto \int \vec { F } \cdot d \vec { r }$ 
B)  $U \propto \int F _ { r } d t$ 
C)  $U \propto r F _ { y }$ 
D)  $U \propto t \vec { F } _ { \gamma }$ 
A)  $U \propto \int \vec { F } \cdot d \vec { r }$ 
B)  $U \propto \int F _ { r } d t$ 
C)  $U \propto r F _ { y }$ 
D)  $U \propto t \vec { F } _ { \gamma }$

Exam 9: Gravitation

An object has a weight of 100 N on the surface of the Earth. If the object is moved to 2RE above the surface of the Earth, its weight is

The mass of Mars is 6.42 ×\times× 1023 kg, and the radius of the planet is 3.40 ×\times× 106 m. The acceleration due to gravity on the surface of Mars is

The Earth's radius is 6.4 ×\times× 106 m. The acceleration due to gravity (in g's) that is experienced by an object at a distance of 150 miles (240 km) above the Earth's surface is

Low Earth orbit (LEO) is approximately 150 miles (240 km) above the surface of the Earth. The radius and mass of the Earth are 6.4 ×\times× 106 m and 5.98 ×\times× 1024 kg. The escape velocity of an object in LEO is

The gravitational potential energy of a planet orbiting around a star is U0 when the distance between the two objects is r0. If the distance between the planet and the star is increased to 2r0, the gravitational potential energy is

Two masses, M1 = 1022 kg and M2 = 1030 kg, are separated by a distance of 1011 m. The magnitude of the gravitational force between the two masses is

In metric units, the dimensions of the gravitational constant G are

Ignoring friction, the path of a projectile launched at a speed greater than the escape velocity at a planet's surface is

The gravitational force on a satellite in a highly elliptical orbit, after it passes the point of closest approach to the Earth and before it reaches the point of farthest separation from the Earth, has a component

The orbit of Io, a moon of Jupiter, is found to have a period of 1.769 days, and its average distance from the center of Jupiter is 420,000 km. The mass of Jupiter

Kepler's Third Law, where k is a proportionality constant, is

An asteroid has a mass of approximately 1015 kg and a diameter of 10 km. The escape velocity for an object at the surface of the asteroid is

The radius and mass of the Earth are 6.4 ×\times× 106 m and 5.98 ×\times× 1024 kg. Assume that a meteor starts at infinity with zero velocity and is attracted to the Earth. Neglecting friction, the speed at which it will strike the Earth is

A planet in another solar system is found to have twice the radius of the Earth and a mass that is double that of the Earth. The acceleration due to gravity on this other planet is

The gravitational potential energy U for an orbiting body depends on the distance r between it and the orbited body as

Low Earth orbit (LEO) is approximately 150 miles (240 km) above the surface of the Earth. The radius and mass of the Earth are 6.4 ×\times× 106 m and 5.98 ×\times× 1024 kg. The velocity of the space shuttle in LEO

The Moon orbits the Earth with a period of about 28 days. The two bodies are separated by a distance ~ 250,000 miles. An Earth satellite at a distance ~125,000 miles would have a period (in days) of

An Earth satellite in an elliptical orbit "speeds down" (that is, as it comes closer to the Earth, its speed increases). This is consistent with the fact that the gravitational potential energy U of the satellite-Earth system at points closer to the Earth is

The gravitational potential energy U is related to the gravitational force F by an equation of the form

Space, Time, and Mass

Motion Along a Straight Line

Vectors

Motion in Two and Three Dimensions

Newtons Laws of Motion

Further Applications of Newtons Laws

Work and Energy

Conservation of Energy

Systems of Particles

Collisions

Rotation of a Rigid Body

Dynamics of a Rigid Body

Statics and Elasticity

Oscillations

Waves

Sound

Fluid Mechanics

The Ideal Gas

Heat

Thermodynamics

Electric Force and the Electric Charge

The Electric Field

Gauss Law

Electrostatic Potential and Energy

Capacitors and Dielectrics

Currents and Ohms Law

Direct Current Circuits

Magnetic Force and Field

Charges and Currents in Magnetic Fields

Electromagnetic Induction

Alternating Current Circuits

Electromagnetic Waves

Reflection, Refraction, and Optics

Interference and Diffraction

The Theory of Special Relativity

Quanta of Light

Spectral Lines, Bohrs Theory, and Quantum Mechanics

Quantum Structure of Atoms, Molecules, and Solids

Nuclei

Elementary Particles and Cosmology

Filters

An object has a weight of 100 N on the surface of the Earth. If the object is moved to 2R_E above the surface of the Earth, its weight is

The mass of Mars is 6.42 $\times$ 10²³kg, and the radius of the planet is 3.40 $\times$ 10⁶ m. The acceleration due to gravity on the surface of Mars is

The Earth's radius is 6.4 $\times$ 10⁶m. The acceleration due to gravity (in g's) that is experienced by an object at a distance of 150 miles (240 km) above the Earth's surface is

Low Earth orbit (LEO) is approximately 150 miles (240 km) above the surface of the Earth. The radius and mass of the Earth are 6.4 $\times$ 10⁶ m and 5.98 $\times$ 10²⁴ kg. The escape velocity of an object in LEO is

The gravitational potential energy of a planet orbiting around a star is U₀ when the distance between the two objects is r₀. If the distance between the planet and the star is increased to 2r₀, the gravitational potential energy is

Two masses, M₁ = 10²² kg and M₂ = 10³⁰ kg, are separated by a distance of 10¹¹ m. The magnitude of the gravitational force between the two masses is

An asteroid has a mass of approximately 10¹⁵kg and a diameter of 10 km. The escape velocity for an object at the surface of the asteroid is

The radius and mass of the Earth are 6.4 $\times$ 10⁶ m and 5.98 $\times$ 10²⁴ kg. Assume that a meteor starts at infinity with zero velocity and is attracted to the Earth. Neglecting friction, the speed at which it will strike the Earth is

Low Earth orbit (LEO) is approximately 150 miles (240 km) above the surface of the Earth. The radius and mass of the Earth are 6.4 $\times$ 10⁶ m and 5.98 $\times$ 10²⁴ kg. The velocity of the space shuttle in LEO