Astronomy Chapter 4-4.3

When a spinning ice skater pulls in his arms, he spins faster because _________.

his angular momentum must be conserved, so reducing his radius must increase his speed of rotation

Which of the following are allowed orbital paths under gravity?

hyperbolic parabolic elliptical

As a giant cloud of gas collapses due to gravity, you would expect its rate of rotation to

increase

The amount of gravitational potential energy released as an object falls depends on

its mass and the distance it falls, as well as the rate of gravitational acceleration.

Rapidly moving comets have more BLANK energy than slowly moving ones

kinetic

Suppose two objects are attracting each other gravitationally. If you double the distance between them, the strength of their gravitational attraction __________.

decreases by a factor of 4 (Gravity follows an inverse sqaure law with distance, so doubling the distance between them decreases the strength of the attraction by a factor of 22 = 4. )

If the United States obtained all its energy from oil, how much oil would be needed each year?

1×10^13 liters

Which of the following is the reason for the leap years?

Earth year being a non-integer number of Earth days

Which person is weightless?

A child in the air as she plays on a trampoline.

Which of the following represents a change from potential energy to kinetic energy?

A rock starting from rest on a high cliff, then moving faster and faster as it falls

Considering Einstein's famous equation, E = mc2, which of the following statements is true?

A small amount of mass can be turned into a large amount of energy.

The fact that the Voyager spacecraft continues to travel out of the solar system, even though its rockets have no fuel, is an example of

Newton's first law of motion.

a conserved quantity?

energy radiation angular momentum momentum

Radiative energy is

energy carried by light.

Which of the following is a form of electrical potential energy?

energy coming to your house from power companies

radiative energy

energy in light. Sunlight carries this form of energy, as do other forms of light including X-rays and radio waves

potential energy

energy that is stored. Two examples of potential energy are breakfast cereal, which has chemical potential energy, and a heavy book on the top shelf at the library, which has gravitational potential energy.

T/F When energy is converted from one form to another, a tiny amount is inevitably lost

false

The escape velocity from Earth is greater for larger rockets than for small ones

fasle

As an interstellar gas cloud shrinks in size, its gravitational potential energy:

gradually transforms into other forms of energy

An asteroid that is moving farther from the Sun is gaining BLANK energy.

gravitational potential

In which of the following cases would you feel weightless?

while falling from a roof

Absolute zero is

0 Kelvin

Which of the following describes a speed, according to an astronomer?

10 light-years per 1 million years

The acceleration of gravity on Earth is approximately 10 m/s2 (more precisely, 9.8 m/s2). If you drop a rock from a tall building, about how fast will it be falling after 3 seconds?

30 m/s

Standing on the surface of the Earth you drop a rock down a well and it falls for 5 seconds before hitting the bottom. How fast is it moving when it hits the bottom of the well? Neglect air resistance.

50 m/s

Of the temperature ranges below, which range represents the smallest range of actual temperature?

50-100° Fahrenheit

If your mass is 60 kg on Earth, what would your mass be on the Moon?

60kg

What is the acceleration of gravity of Earth?

9.8 m/s2 downward

Choose the correct description of an object that is accelerating?

A car going around a circular track at a steady 100 miles per hour.

Liquid water boils at 100. A typical room temperature is 24 .Water freezes into ice at 0.

CELCIUS

Compare the energy of a 1-megaton hydrogen bomb to the energy released by a major earthquake.

Eearthquake/Ebomb = 5

Compare the Sun's annual energy output to the energy released by a supernova.

Esupernova/ESun∼10^11

A hot summer day might be 100.Ice cream is stored in freezers at 26.

FAHRENHEIT

Consider the statement "There's no gravity in space." This statement is:

FALSE

If you double the mass of fusion material in a hydrogen bomb, you quadruple the amount of energy generated.

False!

If you want to make a rocket turn left, you need to:

Fire an engine that shoots out gas to the right.

How does the Space Shuttle take off?

Hot gas shoots out from the rocket and, by conservation of momentum, the shuttle moves in the opposite direction

Where does the energy come from that your body uses to keep you alive?

It comes from the foods you eat.

What would happen if the Space Shuttle were launched with a speed greater than Earth's escape velocity?

It would travel away from Earth into the solar system.

Water boils into gas phase at 373.15.The coldest possibletemperature is 0.

KELVIN

All of the following are true. Which of the following gives evidence that Earth's orbit is not perfectly circular?

The Sun's angular size changes throughout the year. Earth's seasons are not of exactly equal length.

Which of the following examples describes a situation where a car is experiencing a net force?

The car is making a gradual turn.

You are standing on a scale in an elevator. Suddenly you notice your weight decreases. What do you conclude?

The elevator is accelerating downwards.

When a rock is held above the ground, we say it has some potential energy. When we let it go, it falls and we say the potential energy is converted to kinetic energy. Finally, the rock hits the ground. What has happened to the energy?

The energy goes to producing sound and to heating the ground, rock, and surrounding air.

A basketball player jumps to make a basket, and remains in the air for a moment. A sportscaster, talking about the game, then remarks that she has "defied gravity." Which of the following accurately describes the situation?

The player produced enough force with her legs to accelerate up into the air, and gravity brought her back down with an acceleration of 9.8 m/s2.

Which of the following statements correctly describes the law of conservation of energy?

The total quantity of energy in the universe never changes.

Suppose you heat up an oven and boil a pot of water. Which of the following explains why you would be burned by sticking your hand briefly in the pot but not by sticking your hand briefly in the oven?

The water has a higher heat content than the oven because of density.

If you are driving at 30 miles per hour and increase your speed to 60 miles per hour, you quadruple your kinetic energy.

True

Which of the following statements is not one of Newton's laws of motion?

What goes up must come down.

Which of the following scenarios correctly demonstrates the transformation of mass into energy as given by Einstein's equation, E = mc2?

When hydrogen is fused into helium, whether in the Sun or in a nuclear bomb, the mass difference is turned into energy.

Suppose you lived on the Moon. Which of the following would be true?

Your weight would be less than your weight on Earth, but your mass would be the same as it is on Earth.

Which object has the most kinetic energy?

a 2-ton truck moving 90 km/hr

An apple contains BLANK energy that your body can convert into other forms energy.

chemical potential

Gasoline is useful in cars because it has

chemical potential energy

A skater can spin faster by pulling her arms closer to her body or spin slower by spreading her arms out from her body. This is due to

conservation of angular momentum

Suppose an object is moving in a straight line at 50 miles/hr. According to Newton's first law of motion, the object will

continue to move in the same way until it is acted upon by a force

If an object's velocity is doubled, its momentum is

doubled

Which of the following is an example in which you are traveling at constant speed but not at constant velocity?

driving around in a circle at exactly 100 km/hr

The ultimate source of energy that powers the Sun is

mass energy of hydrogen fusing into helium.

Newton's second law of motion tells us that the net force applied to an object equals its

mass times acceleration

Momentum is defined as

mass times velocity.

Compared to their values on Earth, on another planet your

mass would be the same but your weight would be different.

What quantities does angular momentum depend upon?

mass, velocity, and radius

Nuclear fusion in stars converts some of the BLANK of hydrogen nuclei into light and heat.

mass-energy

units of energy

newton meter joule British thermal unit calorie

The light from Polaris travels through space in the form of BLANK energy.

radiative

What does temperature measure?

the average kinetic energy of particles in a substance

kinetic energy

the energy an object has due to its motion. Two examples are a car driving down the highway or the movements of the molecules of liquid in a cup of hot coffee.

In the formula E = mc2, what does E represent?

the mass-energy, or potential energy stored in an object's mass

Compared to its angular momentum when it is farthest from the Sun, Earth's angular momentum when it is nearest to the Sun is:

the same

Suppose that two objects collide. Which of the following things is NOT the same both before and after the collision?

the total temperature of the objects

Due to its much higher density, water heated to 80 degrees (Celsius) contains more BLANK energy than air at the same temperature.

thermal