PHA TEST ONE
Which of the following statements explains why Earth orbits the Sun instead of the Sun orbiting Earth?
Because the Sun has the larger mass, it accelerates less in response to the gravitational force between the two bodies.
What model says that: Electrons orbit the nucleus like planets orbiting the Sun, but can only have specific energy levels.
Bohr model
Suppose two comets of equal mass are in circular orbits around the same star. Comet A's orbit has 3 times the radius of Comet B's orbit. Which of the following is true?
Comet B feels 9 times the gravitational force from the star compared to Comet A.
How was our Solar System formed?
From a collapsing cloud of gas
What causes a nebula to collapse?
Gravity
What model says that: Atoms are indivisible.
Greek model
What are nebulae made of, mostly?
Hydrogen and helium
An idea that is based on evidence but requires further testing
Hypothesis
If the ground pushed me upward with a normal force that were weaker than the gravitational force applied by the Earth, what would be happening?
I would be falling through the ground.
If the ground pushed me upward with a normal force that were stronger than the gravitational force applied by the Earth, what would be happening?
I would be jumping up.
As the Moon orbits the Earth, in which direction is it accelerating? Assume the Moon is in a circular orbit with constant speed.
Inward, toward the Earth
As Earth orbits the Sun, in which direction is it accelerating? Assume the Earth is in a circular orbit with constant speed.
Inward, toward the Sun
A moon in a circular orbit
Inward, toward the center of the curved path
According to Galileo's Law of Falling, how do objects in freefall move?
With constant acceleration
Suppose two asteroids of equal mass are in circular orbits around the same star. Asteroid A's orbit has twice the radius of Asteroid B's orbit. Which of the following is true?
Asteroid B feels 4 times the gravitational force from the star compared to Asteroid A.
According to the Scientific Process, what is the best way to discover truth?
Perform an observation or experiment
gigasecond (Gs)
1 billion seconds
Size of a fingernail
1 cm
Large pill
1 g
Quart of milk
1 kg
Distance across a small town
1 km
Length of an adult human's arm
1 m
Mosquito
1 mg
megasecond (Ms)
1 million seconds
Thickness of a very small wire
1 mm
Small truck
1,000 kg
Distance across France
1,000 km
kilosecond (ks)
1,000 seconds
microsecond (s)
1/1,000,000 seconds
millisecond (ms)
1/1000 seconds
Which of the following quantities are speeds? Choose all that apply. 10 km/s northbound 10 km/s 5 mph 5 mph northbound
10 km/s 5 mph
Which of the following quantities are velocities? Choose all that apply. 10 km/s eastbound 5 mph 10 km/s 5 mph northbound
10 km/s eastbound 5 mph northbound
Which will accelerate more? Do NOT choose "aliens".
A 1,000 kg cart being pushed with 100 N of force
Which will accelerate more?
A 10 kg cart being pushed with 100 N of force
Which will accelerate more? Answers: A 1,000 kg cart being pushed with 100 N of force A 10,000 kg cart being pushed with 100 N of force
A 10,000 kg cart being pushed with 100 N of force
According to Aristotle's hypothesis, which falls faster? (Do not choose "aliens")
A heavy object
Which of the following statements explains why Moon orbits the Earth and not the other way around?
Because the Earth has the larger mass, the Moon accelerates more in response to the gravitational force between the two bodies.
An elevator moving upward, slowing down
Downward
Test of an idea by taking data in a controlled setting such as a laboratory
Experiment
If the ground is pushing me upward with a normal force that is weaker than the gravitational force applied by the Earth, what am I doing?
Falling through the ground.
A 5,000,000 kg asteroid flying through space at 10 m/s has more momentum than an asteroid with the same mass flying twice the speed.
False
Because Mars has a smaller acceleration due to gravity than Earth, I would have less mass on Mars than on Earth.
False
True or false: According to modern experiments, heavy objects always fall faster than light objects.
False
If the ground is pushing me upward with a normal force that is stronger than the gravitational force applied by the Earth, what am I doing?
Jumping up
Suppose a moving car hits a dime-size ball of hail. Which object exerts a stronger force on the other?
Neither
Suppose a moving car hits a flying tennis ball. Which object exerts a stronger force on the other?
Neither
Match each subatomic particle with its electric charge. Neutron aliens Electron Proton
Neutron = neutral Proton = Positive Electron = negative Aliens = Aliens
An elevator moving upward at constant speed
Not accelerating
Suppose a spage ship is flying through space. It is subjected to a force of 50 N leftward and 50 N rightward at the same time. In what way will it accelerate?
Not at all
Why does the Sun shine?
Nuclear fusion in the Sun's core
Test of an idea by taking data from an environment in nature
Observation
A belief that may or may not be backed by evidence.
Opinion
Suppose a friend tells you that hot water freezes faster than cold water but you are skeptical of this claim. According to the Scientific Process, what is the best way to determine whether the claim is true?
Perform a carefully controlled observation or experiment
What model says that: Electrons orbit the nucleus like planets orbiting the Sun, and can have arbitrary energies.
Planetary model
Which subatomic particles are part of the nucleus? Choose all that apply. Proton Neutron Answers: aliens Proton Neutron Electron
Proton Neutron
What model says that: Electrons are clouds or waves surrounding the nucleus.
Quantum model
Suppose a space ship is flying away from Earth. It is subjected to a force in the backward direction. What will it do?
Slow down
Suppose a space ship is flying away from you through space. It is subjected to force in the direction toward you. What will it do?
Slow down
Suppose a space ship is flying through space. It is subjected to a force of 100 N in the backward direction. What will it do?
Slow down
Where in our Galaxy are stars usually formed?
Spiral arms
Suppose a moving car hits a flying tennis ball. Which object accelerates more?
Tennis ball
Suppose a moving car hits a flying tennis ball. Which object accelerates more? Do not choose "aliens".
Tennis ball, because it is less massive.
Where is most of the mass in our Solar System located?
The Sun
The Sun is more massive than the Jupiter. Which of the following is true about their gravitational interaction?
The Sun and Jupiter exert equal forces on one another but in opposite directions.
The Sun is more massive than the Mercury, the innermost planet. Which of the following is true about their gravitational interaction?
The Sun and Mercury exert equal forces on one another but in opposite directions.
Suppose an astronaut is floating in the International Space Station, which is orbiting the Earth. Which of the following is true?
The astronaut is both in orbit and in freefall.
According to modern experiments, why does a bowling ball fall faster than a piece of paper?
The bowlig ball feels less air resistance.
According to modern experiments, why does a bowling ball fall faster than a piece of paper?
The bowling ball feels less air resistance.
Suppose a dog, after standing at rest, suddenly sprints. What provides the force that accelerates the dog?
The ground
Suppose a giraffe, after standing at rest, suddenly sprints. What provides the force that accelerates the giraffe?
The ground
If I am standing on a frozen lake and the ice is holding me steady, which of the following statements are true? Choose all that apply:
The normal force is equally strong as my weight. There is no net force on me.
If I am standing on a table and the table is holding me steady, which of the following statements are true? Choose all that apply: The gravitational force on me is stronger than the normal force on me. The normal force on me is stronger than the gravitational force on me. There are no forces on me at all. The normal force is equally strong as my weight. There is no net force on me.
The normal force is equally strong as my weight. There is no net force on me.
Suppose a pencil is floating in the International Space Station, which is orbiting the Earth. Which of the following is true?
The pencil is both in orbit and in freefall.
When two comets collide, what happens to the total momentum of the system?
The total momentum stays the same.
A 5,000,000 kg asteroid flying through space at 10 m/s has more momentum than an asteroid with half its mass flying at the same speed.
True
Because Mars has a smaller acceleration due to gravity than Earth, I would weigh less on Mars than on Earth.
True
Because the planet Venus has a slightly smaller acceleration due to gravity than Earth, I would weigh slightly less on Venus than on Earth.
True
An elevator moving upward, speeding up
Upward
True or false: According to modern experiments, heavy objects always fall faster than light objects.
false
