3.1 Newton's Universal Law of Gravitation

The distance between the Earth and the Moon centres is 3.8 × 10⁸ m. The mass of the Earth is, m_e= 5.97 × 10²⁴ kg

and the mass of the Moon is, m_m = 7.36 × 10²² kg. What is the gravitational force between the Earth and the Moon?

(G = 6.67 × 10^-11 N m^-2 kg^-2)

• 2.03 x 10²¹ N

• 2.03 x 10²⁰ N

• 4.03 x 10²⁰ N

• 4.03 x 10²² N

The mass of the Sun is 2.0 × 10³⁰ kg and the mass of the Earth is, m_e = 5.97 × 10²⁴kg. The distance from the Earth is 1.50 × 10¹¹km. What is the gravitational force between the Sun and the Earth?

(G = 6.67 × 10^-11 N m^-2 kg^-2)

• 1.54 x 10²² N

• 2.54 x 10²² N

• 3.54 x 10²² N

• 4.54 x 10²² N

A rocket of 2.5 x 10⁴ kg moves from Earth to the moon. The mass of the Earth is m_e = 5.97 × 10²⁴kg. Calculate the Earth’s gravitational force on the rocket when its distance from the Earth is 1.0 x 10⁹ m. (G = 6.67 × 10^-11 N m^-2 kg^-2)

• 9.95 N

• 8.95 N

• 10.95 N

• 9.81 N

A 300 kg satellite is orbiting around the Earth at the height of 550 km. Given that the mass of the Earth is 5.97 × 10²⁴kg and the radius of the Earth is 6.37 × 10⁶ m. What is the value of gravitational acceleration at the location of the satellite?

(G = 6.67 × 10^-11 N m^-2 kg^-2)

• 8.32 ms^-2

• 9.81 ms^-2

• 7.39 ms^-2

• 5.65 ms^-2

Newton’s Universal Law of Gravitation states that the gravitational force between two objects is directly proportional to the product of masses of the two objects and inversely proportional to

• distance between the two objects.

• square of the product of the body’s radii.

• square of the distance between the centres of the two objects.

• cube of the distance between the centres of the two objects.

If the distance between two particles is doubled, what

happened to the gravitational force between them?

• Is reduced to one-fourth of the original value

• Is reduced to half of the original value

• Becomes double

• Becomes four times

If the mass of the Earth becomes four times, what will happen to the value of g?

• Double

• No effect

• Half

• Four times

If the radius of the Earth were to be reduced and its mass were

to remain the same, what happens to the acceleration due to

gravity on the surface of the Earth?

• Remain the same

• Decreases

• Zero

• Increases

Which of the following can be applied by the Universal Law of Gravitation?

• The planets around the Sun

• The Earth and the moon

• The Earth and the apple

• Any pair of bodies

What is the reason for the motion of the Moon on its orbit?

• The gravitational force exerted on the Earth by the Moon.

• The gravitational force exerted by the Sun.

• The gravitational force exerted by the planets.

• The gravitational force exerted on the Moon by the Earth.