Question 1

Which of the following best describes why Newton's law of universal gravitation is still used for satellite motion, even though Einstein's theory of general relativity is more accurate?

Accepted Answer

Newton's law is easier to apply and sufficiently accurate for most practical calculations involving satellites.

Question 2

According to Newton's law of universal gravitation, what happens to the gravitational force between two objects if the distance between them is doubled?

Accepted Answer

The force becomes one-fourth as strong.

Question 3

A projectile is launched horizontally from a cliff. Neglecting air resistance, which statement is true about its horizontal velocity?

Accepted Answer

The horizontal velocity remains constant throughout the motion.

Question 4

Which equation correctly expresses the escape velocity $$v_{esc}$$ from a planet of mass $$M$$ and radius $$R$$?

Accepted Answer

$$v_{esc} = \sqrt{\frac{2GM}{R}}$$

Question 5

A satellite in a circular orbit around Earth has constant speed. Which of the following best explains why its speed does not change?

Accepted Answer

The gravitational force acts perpendicular to the direction of motion, so it does not change the speed.

Question 6

If a satellite moves in an elliptical orbit around Earth, at which point is its kinetic energy greatest?

Accepted Answer

At perigee, when it is closest to Earth.

Question 7

A ball is dropped and another is launched horizontally from the same height at the same time. Neglecting air resistance, which statement is true?

Accepted Answer

Both balls hit the ground at the same time.

Question 8

Why do astronauts in the International Space Station appear weightless?

Accepted Answer

They are in continuous free fall towards Earth, experiencing no normal force.

Question 9

A satellite orbits Earth at a height where the radius from Earth's center is doubled compared to the surface. If the gravitational force at the surface is $$F$$, what is the force at this new height?

Accepted Answer

$$F/4$$

Question 10

Which of the following best describes the path of a projectile under the influence of gravity (neglecting air resistance)?

Accepted Answer

A parabola

Question 11

A satellite in low Earth orbit travels at approximately 8 km/s. What would happen if its tangential speed were reduced to zero?

Accepted Answer

It would fall vertically towards Earth.

Question 12

Which statement about energy conservation in satellite motion is correct?

Accepted Answer

The sum of kinetic and potential energy remains constant throughout the orbit.

Question 13

What is the minimum speed required for an object to escape Earth's gravitational field from the surface?

Accepted Answer

About 11.2 km/s

Question 14

A projectile is launched at an angle above the ground. Neglecting air resistance, what is true about the time to reach maximum height compared to the time to return to the ground?

Accepted Answer

The time to reach maximum height equals the time to return to the ground.

Question 15

Which of the following is NOT a real-world example of gravity in action?

Accepted Answer

A car accelerating on a flat road

Question 16

If a satellite's speed is greater than needed for a circular orbit, what type of path will it follow?

Accepted Answer

An elliptical orbit

Question 17

Which of the following best explains why a satellite does not fall back to Earth?

Accepted Answer

Its tangential speed matches the curvature of Earth, so it keeps missing the surface as it falls.

Question 18

A toolbox is projected rearward at 7 km/s from a spaceship moving at 7 km/s with respect to Earth. What is the speed of the toolbox with respect to Earth?

Accepted Answer

0 km/s

Question 19

Which of the following is true about the vertical and horizontal components of projectile motion (neglecting air resistance)?

Accepted Answer

The horizontal component remains constant, while the vertical component changes due to gravity.

Question 20

What is the period of a satellite in low Earth orbit?

Accepted Answer

About 90 minutes

Projectile and Satellite Motion: Concepts and Applications

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