Physics

Gravitation and Center of Mass

369 Questions

Gravitation and center of mass questions explore gravitational fields, planetary density, and the mechanics of celestial bodies. Test items include calculating gravitational strength on different planets and understanding the Roche Limit. This topic is essential for the physics syllabus of major competitive exams.

Gravitational fieldCenter of massPlanetary densityHill SphereSpace-time curvature

Gravitation and Center of Mass Questions

Multiple choice

If gravity increases when distance decreases, how can the Sun affect Earth 93,000,000 mi. away?

  1. because their masses are so great

  2. because Earth's rotational speed is so fast
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Although gravity decreases with distance, the gravitational force also depends on the masses of the objects. The immense masses of both the Sun and the Earth allow for a strong gravitational attraction despite the vast distance between them.

Multiple choice

Which 2 factors affect gravity?

  1. mass & speed

  2. speed & distance

  3. distance & mass

  4. magnetism & distance
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

According to Newton's law of universal gravitation, the gravitational force between two objects is determined solely by their masses and the distance between them. Speed and magnetism do not affect gravitational force.

Multiple choice

What is the measurement of the gravitational force on Earth?

  1. 9.2 m/s2

  2. 9.8 m/s2

  3. 8.9 m/s2

  4. 10.3 m/s2
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The acceleration due to gravity near the Earth's surface is approximately 9.8 m/s^2. This value represents how fast an object accelerates when in free fall under the influence of Earth's gravity.

Multiple choice

If an object on the moon weighs 30 kilograms, what does it weigh on Earth?

  1. It weighs more because the gravity on the moon is more

  2. It weighs more because in space there is no gravity

  3. It weighs more because the gravity of Earth is greater

  4. It weighs the same weight does not change
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Earth's gravitational acceleration (9.8 m/s²) is about 6 times stronger than the Moon's (1.6 m/s²). While mass remains constant, weight depends on gravity, so the object would weigh more on Earth.

Multiple choice

What factors influence the strength of attraction (gravity) between two objects?

  1. mass and distance

  2. size and density

  3. weight and volume

  4. composition and location in the Universe
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

According to Newton's law of universal gravitation, the force of gravity between two objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

Multiple choice

The definition of mass is

  1. the amount of matter in an object

  2. The amount of space an object takes up

  3. The amount an object weighs on the moon

  4. The physical form of an object (solid, liquid, or gas)
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Mass is defined as the total amount of matter or substance contained within an object, which remains constant regardless of location.

Multiple choice

The force exerted by the moon on Earth is:

  1. Equal to the force of the Earth on the Moon

  2. Is the negative of the force of the Earth on the Moon

  3. is one sixth the force of the Earth on the Moon

  4. Is negative one sixth the force of the Earth on the Moon
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

According to Newton's Third Law, forces exist in action-reaction pairs that are equal in magnitude and opposite in direction. Therefore, the force of Earth on the Moon is the negative of the force of the Moon on Earth.

Multiple choice

Using agrav=Gm/r2 to calculate the gravitational field strength for Mars, m and r represent:

  1. The mass and radius of the Sun

  2. the mass and radius of Mars

  3. the mass of the Sun and the radius of Mars

  4. The Sun's mass and the average distance from Mars to the Sun
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In the formula a_grav = GM/r^2, M represents the mass of the central body creating the gravitational field, and r represents the distance from the center of that body. For Mars, these are the mass and radius of Mars.

Multiple choice

Which of the following does NOT influence the gravitational acceleration acting on a planet?

  1. The mass of the star it orbits

  2. The mass of the planet itself

  3. The gravitational constant, G

  4. The distance from the star it orbits
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Gravitational acceleration on a planet's surface is determined by the planet's mass and radius (g = GM/r^2). The mass of the star it orbits does not affect the surface gravity of the planet itself.

Multiple choice

In Newton's gravitational force equation, G is:

  1. The gravitational constant

  2. given in Nm2/kg2

  3. 6.7x10-11

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In F = G(m1m2/r^2), G is indeed the gravitational constant, its units are Nm^2/kg^2, and its approximate value is 6.67 x 10^-11 Nm^2/kg^2.

Multiple choice

What is a "g-force"?

  1. another word for "gravity"

  2. the gravitational force between earth and the moon

  3. a measure of acceleration

  4. A NASA crime-fighting unit
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A g-force is a measurement of acceleration expressed in multiples of the acceleration due to gravity on Earth.

Multiple choice

The gravity on _____________ is greater

  1. the moon

  2. space

  3. the earth

  4. in school
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Gravity is proportional to mass; Earth has significantly more mass than the moon, resulting in stronger gravity.