Question 1

Imagine another solar system, with a star of the same mass as the Sun. Suppose a planet with a mass twice that of Earth (2MEarth)orbits at a distance of 1 AU from the star. What is the orbital period of this planet?

Accepted Answer

The orbital period of a planet depends on the distance from its star and the mass of the star, not the mass of the planet. Since the star has the same mass as the Sun and the planet orbits at a distance of 1 AU (the same as Earth), the orbital period would be 1 year, just like Earth's.

Question 2

Newton's version of Kepler's third law states: In this equation, what does G represent?

Accepted Answer

G represents the universal gravitational constant in Newton's version of Kepler's third law.

Question 3

At which lunar phase(s)are tides most pronounced (for example, the highest high tides)?

Accepted Answer

Both new and full moons have the most pronounced tides, with the highest high tides and lowest low tides. This is because during these phases, the gravitational forces of the Sun and Moon combine to create a stronger tidal pull on the Earth's oceans.

Question 4

The force due to gravity between two objects can be described using the equation Fg = G M1 M2 / d2. In this equation, what does G represent?

Accepted Answer

G represents the universal gravitational constant, which is a fundamental constant of nature that determines the strength of the gravitational force between two objects. It has a value of approximately 6.674 × 10^-11 N(m/kg)^2.

Question 5

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

Accepted Answer

Your mass remains the same regardless of location in the universe. The difference on the Moon would be in your weight due to the lower gravitational pull, not your mass.

Question 6

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

Accepted Answer

In the formula E=mc2, E represents the mass-energy or potential energy stored in an object's mass.

Question 7

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

Accepted Answer

Temperature is a measure of the average kinetic energy of the particles in an object. In a collision, the total temperature of the objects is not a conserved quantity and it can change due to the conversion of some of the kinetic energy into other forms (such as sound, deformation or heat). On the other hand, momentum, energy and angular momentum are all conserved quantities in a collision, meaning their total values before and after the collision must be the same.

Question 8

When space probe Voyager 2 passed by Saturn, its speed increased (but not due to firing its engines). What must have happened?

Accepted Answer

According to the Law of Conservation of Energy, energy cannot be created or destroyed, only transferred or transformed. As Voyager 2 passed by Saturn, its gravitational interaction with the planet caused a transfer of energy. Since Voyager 2's speed increased, it means that some of Saturn's energy was transferred to the spacecraft, causing Saturn to lose a very small amount of its orbital energy.

Question 9

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?

Accepted Answer

The velocity of the rock after 3 seconds can be found using the formula: 
v = gt 
where g is the acceleration due to gravity (10 m/s2) and t is the time (3 seconds). 
Plugging in the values, we get: 
v = 10 m/s2 x 3 s = 30 m/s 
Therefore, the rock will be falling at a speed of approximately 30 m/s after 3 seconds, so the answer is D.

Question 10

The speed at which a pool ball moves after being struck by a cue is most directly an example of

Accepted Answer

Newton's second law of motion states that the force applied to an object is equal to the mass of the object multiplied by its acceleration (F=ma). In the case of a pool ball being struck by a cue, the force applied by the cue causes the ball to accelerate and increase in speed, in accordance with this law.

Question 11

A net force acting on an object will always cause a change in the object's _.

Accepted Answer

A net force acting on an object will always cause a change in the object's momentum, according to Newton's second law of motion. This change in momentum can manifest as a change in speed, direction, or both, but does not inherently change the object's mass.

Question 12

The force of gravity is an inverse square law. This means that, if you double the distance between two large masses, the gravitational force between them

Accepted Answer

Answer Key Testname: C4

Question 13

Suppose you drop a 10- pound weight and a 5- pound weight on the Moon, both from the same height at the same time. What will happen?

Accepted Answer

Both weights will hit the ground at the same time because they will experience the same acceleration due to gravity on the Moon. The acceleration due to gravity on the Moon is about 1/6th of that on Earth, so both weights will fall more slowly than they would on Earth, but they will still fall at the same rate.

Question 14

Absolute zero is .

Accepted Answer

Absolute zero is defined as the lowest possible temperature that can be reached, where all matter ceases to move due to a lack of thermal energy. It is measured in Kelvin, with 0 Kelvin representing absolute zero. The other temperature scales, Celsius and Fahrenheit, do not have a true zero point that represents the absence of thermal energy.

Question 15

Which of the following represents a case in which you are not accelerating?

Accepted Answer

When driving in a straight line at constant speed (in this case, 60 miles per hour), there is no change in velocity and therefore no acceleration.

Question 16

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

Accepted Answer

When the elevator accelerates downwards, the support force from the scale decreases, which makes you feel lighter, hence your weight appears to decrease on the scale. Constant velocity motion, either upwards or downwards, would not cause a change in your apparent weight on the scale, and neither would an upward acceleration (which would actually make you feel heavier).

Question 17

According to the universal law of gravitation, the force due to gravity is

Accepted Answer

According to the universal law of gravitation, the force due to gravity between two objects is inversely proportional to the square of their distance apart. This means that as the distance between two objects increases, the gravitational force decreases exponentially.

Question 18

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

Accepted Answer

The law of conservation of energy states that the total amount of energy in a closed system remains constant and cannot be created or destroyed, only transferred or transformed from one form to another. This means that the total quantity of energy in the universe never changes, making option B the correct statement.

Question 19

What is the difference between a bound orbit and an unbound orbit around the Sun?

Accepted Answer

A bound orbit is one in which the object follows the same path around the Sun repeatedly, while an unbound orbit is one in which the object approaches the Sun only once and then does not return. The other options listed are incorrect: both bound and unbound orbits are allowed by the universal law of gravitation, and both can be either circular or elliptical depending on the object's speed and distance from the Sun. Furthermore, both bound and unbound orbits are subject to gravitational attraction from the Sun.

Question 20

Radiative energy is .

Accepted Answer

Radiative energy refers to energy carried by electromagnetic radiation or light.

Quiz 4: Making Sense of the Universe: Understanding Motion, Energy, and Gravity

Imagine another solar system, with a star of the same mass as the Sun. Suppose a planet with a mass twice that of Earth (2MEarth) orbits at a distance of 1 AU from the star. What is the orbital period of this planet?