Deck 3: Laws of Motion

Question 1

An unbound orbit results when a satellite has a velocity greater than the escape velocity.

Answer 1

True

Question 2

Johannes Kepler found that the gravitational force between the Sun and Earth is inversely proportional to the mass of the Sun.

Answer 2

False

Question 3

In the figure below,the woman pushes on each object with the same force.If the resulting acceleration of the 100 kg object is 1 m/s²,then the acceleration of the 200 kg object is 2 m/s².

Answer 3

False

Question 4

A planet travels fastest when it is closest to the Sun.

Question 5

Which scientist ended up under house arrest due to his support of the heliocentric model?

A) Galileo Galilei
B) Isaac Newton
C) Johannes Kepler
D) Tycho Brahe

Question 6

A kilogram of lead has more mass than a kilogram of feathers.

Question 7

The only acceleration you experience on a merry-go-round is when it starts or stops.

Question 8

To find the mass of Jupiter,we only need to know the semimajor axis and period of one of its moons.

Question 9

In which of the following situations would the object be experiencing an unbalanced force?

A) A truck at rest
B) An car moving at constant speed turning a corner
C) A rocket moving at a constant speed straight up away from the Earth
D) A car moving at a constant speed towards the right

Question 10

What force holds planets in their orbits?

A) Air resistance
B) Friction
C) Electromagnetic
D) Gravity

Question 11

An astronaut orbiting the Earth in a circular orbit at a constant speed does not feel the force of gravity because his/her acceleration is zero.

Question 12

Mass and weight are different names for the same physical property of matter.

Question 13

Isaac Newton was the first scientist to use a telescope for astronomical discoveries.

Question 14

More massive objects fall faster in the Earth's gravitational field than less massive objects.

Question 15

Once two objects are far enough away from each other,they no longer exert any gravitational attraction on each other.

Question 16

In the absence of air friction,a 0.001-kg piece of paper and a 0.1-kg notebook are dropped from the same height and allowed to fall to the ground.How do their accelerations compare?

A) The accelerations are the same.
B) The notebook's acceleration is 100 times faster than the paper's acceleration.
C) The notebook's acceleration is 1,000 times faster than the paper's acceleration.
D) The paper's acceleration is 100 times faster than the notebook's acceleration.

Question 17

In the figure below,the woman pushes on each object with the same force.If the resulting acceleration of the 100 kg object is 2 m/s²,then the acceleration of the 200 kg object is 1 m/s².

Question 18

Astronauts in the space station feel weightless as they orbit the earth because there is no gravity acting on them.

Question 19

A satellite is a less massive object in free fall around a more massive object.

Question 20

Gravity holds planets in orbit.

Question 21

The force of gravity that an object has is directly related to its:

A) inertia
B) size
C) mass
D) density

Question 22

Once a satellite's velocity at closest approach equals or exceeds the __________ velocity,it is in an unbound orbit.

A) tangential
B) linear
C) circular
D) escape

Question 23

If an object is moving in a circular orbit at a constant speed,which of the following is FALSE?

A) Its acceleration is not zero.
B) Its acceleration is zero.
C) Its velocity is not zero.
D) There is an unbalanced force acting on it.

Question 24

What type of orbit results when a satellite has a velocity greater than the escape velocity?

A) Unbound
B) Bound
C) Circular
D) Linear

Question 25

The natural tendency of an object to resist changes in motion is called:

A) inertia
B) weight
C) acceleration
D) mass

Question 26

Which of the following is true about a comet that is on an elliptical orbit around the Sun?

A) The comet's speed is greatest when it is farthest from the Sun.
B) The comet's speed is greatest when it is nearest the Sun.
C) This comet's speed is zero.
D) The comet's speed is constant because its mass and the Sun's mass stay approximately the same.

Question 27

Which of the following properties of an astronaut changes when he/she is standing on the Moon,relative to when the astronaut is standing on Earth?

A) Weight
B) Mass
C) Inertia
D) All of the above

Question 28

Which of the following did NOT require the use of a telescope to observe?

A) Spots on the Sun
B) Retrograde motion of the planets
C) Phases of Venus
D) Jupiter's moons

Question 29

Examine the figure below.What is the name of the force that the string exerts on the ball?

A) Centripetal force
B) Gravity
C) Friction force
D) Air resistance

Question 30

Your weight is directly proportional to your ___________.

A) height
B) age
C) mass
D) altitude

Question 31

Which of Newton's Laws states that if an unbalanced force acts on an object,then the object's motion changes?

A) Newton's 1^st Law
B) Newton's 2^nd Law
C) Newton's 3^rd Law
D) Newton's Law of Gravitation

Question 32

Newton's first law states that objects in motion:

A) eventually come to rest
B) experience an unbalanced force
C) experience a nonzero acceleration
D) stay in motion

Question 33

__________ hypothesized that planetary motions could be explained by a force arising from the attraction between the mass of the planet and Sun that decreased with the square of the distance between them.

A) Johannes Kepler
B) Isaac Newton
C) Tycho Brahe
D) Nicolaus Copernicus

Question 34

Which of the following is NOT an example of a satellite of the Earth?

A) The Moon
B) The Hubble Telescope
C) The Sun
D) Communication satellites

Question 35

Two rocks (call them S and T)are a distance of 50 km from one another.Rock S has 20 times the mass of rock T.Which rock will move faster if the only force involved is their mutual gravitational attraction?

A) Rock S
B) Both rocks will move at the same speed.
C) Rock T
D) Not enough information is available to answer.

Question 36

If your weight on Earth was 500 N,what would your weight be on the Moon?

A) 83 N
B) 125 N
C) 250 N
D) 500 N

Question 37

In a spaceship orbiting Earth,two astronauts want to measure the mass of a mouse.How can they easily do it if they are in constant free fall?

A) Place the mouse on a spring-loaded scale and weigh it.
B) Measure the gravitational attraction between the mouse and a steel ball of known mass.
C) Drop the mouse from the top of the shuttle to its bottom.
D) Push on the mouse with a known force and measure its acceleration.

Question 38

If a 100-kg astronaut pushes on a 5,000-kg satellite and the satellite experiences an acceleration of 0.1 m/s²,what is the acceleration experienced by the astronaut in the opposite direction?

A) 5 m/s²
B) 10 m/s²
C) 50 m/s²
D) 0.1 m/s²

Question 39

An empirical science is one that is based on:

A) assumptions
B) calculus
C) computer models
D) observed data

Question 40

In the figure below,the force of gravity is drawn in the picture.This represents Earth's gravity pulling down on the man.According to Newton's third law,what is the other half of this pair of forces?

A) The floor pushing up on the man.
B) The man pushing on the floor.
C) The man's gravity pulling up on the Earth.
D) The floor pushing backwards on the man.

Question 41

The force of gravity between the Earth and the Sun is __________ the force of gravity between the Earth and the Moon.For reference,the average distance between the Earth and the Moon is 0.003 AU,the mass of the Moon is 7 × 10²² kg,and the mass of the Sun is 2 × 10³⁰ kg.

A) 86,000 times larger than
B) 260 times larger than
C) 140 times smaller than
D) 6,400 times smaller than

Question 42

In the figure below,if the acceleration of the container is 2 m/s²,with what force did the woman push?

A) 50 N
B) 100 N
C) 150 N
D) 200 N

Question 43

In a period of three months,a planet travels 30,000 km with an average speed of 10.5 km/s.Some time later,the same planet travels 65,000 km in three months.How fast is the planet traveling at this later time? During which period is the planet closer to the Sun?

Question 44

If you weighed 150 lbs on Earth,what would you weigh on Mars? For reference,Mars has a mass that is 0.1 times the Earth's mass and Mars has a radius that is 0.5 times the Earth's radius.

A) 30 lbs
B) 110 lbs
C) 76 lbs
D) 60 lbs

Question 45

In terms of frames of reference,explain why an object moving in a straight line at constant speed remains in motion.

Question 46

If we wanted to increase the Hubble Space Telescope's altitude above the Earth and keep it in a stable orbit,we also would need to:

A) increase its orbital speed
B) increase its weight
C) decrease its weight
D) decrease its orbital speed.

Question 47

What is your acceleration if you go from 0 to 60 mph in 4 seconds?

A) 60 mph/s
B) 30 mph/s
C) 15 mph/s
D) 8.5 mph/s

Question 48

What is required to change an object's motion?

Question 49

In the figure below,if the woman pushes with a force of 50 N,what will the acceleration of the container be?

A) 0.5 m/s²
B) 0.75 m/s²
C) 1 m/s²
D) 2 m/s²

Question 50

Suppose you are suddenly transported to a planet with 1/4 the mass of Earth but the same radius as the Earth.Your weight would __________ by a factor of __________.

A) increase; 4
B) increase; 16
C) decrease; 4
D) decrease; 16

Question 51

Name the two ways in which an object's motion (meaning its velocity)can experience a nonzero acceleration.

Question 52

If the distance between the Earth and Sun were cut in half,the gravitational force between these two objects would:

A) decrease by 4
B) decrease by 2
C) increase by 2
D) increase by 4

Question 53

Suppose you are suddenly transported to a planet with 1/4 the radius of Earth but the same mass as the Earth.Your weight would __________ by a factor of __________.

A) increase; 4
B) increase; 16
C) decrease; 4
D) decrease; 16

Question 54

According to Newton's third law,forces come in pairs.Two forces in the figure below are labeled.Label the other half of the pairs.

Question 55

In the figure below,draw an arrow representing the direction of the acceleration in each case.If the acceleration is zero,write zero.

Question 56

What two pieces of information do we need to know about the Earth in order to calculate the mass of the Sun?

A) The semimajor axis of the Earth's orbit is 1 AU and the mass of the Earth is 6 × 10²⁴ kg.
B) The semimajor axis of the Earth's orbit is 1 AU and the Earth takes 1 year to orbit the Sun.
C) The radius of the Earth is 6.4 × 10³ km and the Earth takes 1 year to orbit the Sun.
D) The radius of the Earth is 6.4 × 10³ km and the mass of the Earth is 6 × 10²⁴ kg.

Question 57

Astronauts orbiting Earth in the space shuttle feel weightless in space because:

A) they are farther away from the Earth
B) they eat less food while in orbit
C) the added gravitational pull of the Moon balances the Earth's gravitational pull
D) they are in constant free fall around the Earth

Question 58

List at least three discoveries Galileo made by making astronomical observations through a telescope.

Question 59

What is your acceleration if you go from 0 to 30 m/s in 3 seconds?

A) 5 m/s²
B) 10 m/s²
C) 15 m/s²
D) 30 m/s²

Question 60

You apply a force of 10 N to a grocery cart in order to get an acceleration of 0.5 m/s².If you apply a force of 20 N to the same grocery cart,its acceleration will be:

A) 10 m/s²
B) 1 m/s²
C) 0.5 m/s²
D) 0.25 m/s²

Question 61

Examine the figure below.If the woman pushes with a force of 200 N,what is the acceleration of the container?

Question 62

Explain the difference between being weightless and being in free fall.

Question 63

What acceleration would result from a 5-N force acting on a 3-kg object? (A Newton [N] has units of kg m/s².)

Question 64

What information would you need to obtain about one of the moons of the planet Jupiter in order to measure the mass of Jupiter?

Question 65

Examine the figure below.If the acceleration of the container is 2 m/s²,with what force did the woman push?

Question 66

Astronauts feel "weightless" on the Moon.Using Newton's universal law of gravitation,explain why this statement is true or false and why astronauts experience this feeling.

Question 67

If a 100-kg asteroid collides with Earth,causing the asteroid to decelerate in one second from 1,000 m/s to 0 m/s,what acceleration will Earth experience according to Newton's third law? (Earth has a mass of approximately 6 × 10²⁴ kg.)

Question 68

The figure below shows Newton's cannonball thought experiment.At the three locations of the cannonball shown,draw and label arrows representing the circular velocity and acceleration.

Question 69

How much stronger is the gravitational force of the Sun on the Earth compared to the gravitational force of the Sun on Pluto? Note that Pluto's semimajor axis is 40 AU and its mass is 0.002 times the mass of the Earth.

Question 70

Is there a difference in your weight between when you are on top of a mountain at 1,000 m above sea level compared to when you are sitting in a classroom at 10 m above sea level?