Astronomy Ch4

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

Momentum is defined as

mass times velocity

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

doubled

As long as an object is not gaining or losing mass, a net force on the object will cause a change in

velocity

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

60 kilograms

In which of the following cases would you feel weightless?

while falling from a roof

Which of the following is not a conserved quantity?

Radiation

Radiative energy is

energy carried by light

What does temperature measure?

The average kinetic energy of particles in a substance

A basketball player jumps to make a basket and remains in the air for a moment. A sportscaster 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 upward and remains above ground only until the acceleration of gravity brought her back down

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 a straight line at 50 miles/hr until it is acted upon by a net force

Consider Newton's second law states, often written as force = mass × acceleration. If a known force is applied to an object with a known mass, what does this law predict for the object's acceleration?

Acceleration = force / mass

Angular momentum depends upon

mass, velocity and radius

Which law explains why a skater can spin faster by pulling his arms closer to his body, or spin slower by spreading his arms out

the law of conservation of angular momentum

Suppose the Sun were to suddenly shrink in size but its mass remained the same. According to the law of conservation of angular momentum, what would happen?

The Sun rate of rotation would increase

Which of the following has the most kinetic energy?

A 2-ton truck moving 40 km/hr

On a hot day, molecules of air ________ than on a cold day

move faster on average

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

its mass, the distance it falls, and the acceleration of gravity

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

The mass-energy or potential energy stored in an object's mass

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

Energy can change between many different forms, such as potential, kinetic, and thermal, but the total quantity of energy in the universe never changes.

Based on fundamental laws of motion and gravity, which of the following best explains why Kepler's second law (planets move faster in the parts of their orbit that are closer to the Sun and slower when they are farther from the Sun) is true?

A planet's angular momentum must be conserved as it moves around its orbit.

As an interstellar gas cloud shrinks in size, the law of conservation of angular momentum predicts it will

rotate faster