Below you will find a set of 5 conceptual and numerical revision questions selected randomly from lots of questions I have put together covering the material in Chapter 11, "Gravity". This includes questions on Kepler's 3rd Law, Newton's Law of Gravitation, satellite motion, escape speed and gravitational potential energy. When you have finished the quiz, click on the "Submit Quiz" button at the bottom and within seconds it will be automatically graded and the results returned to you!

To select a new set of questions click on the "Reload" or "Refresh" button on your browser. You may find some of the questions duplicated but that's the nature of a random selection. Try it a few times ... it's not fattening and you may learn something!

Many thanks to Mark Wood for producing the quiz-maker code.

Q1: A 2400 kg satellite is in a circular orbit around a planet. The satellite travels with a constant speed of 6.67 ¥ 10³ m/s with an orbital radius of 8.92 ¥ 10⁶ m.

At the instant shown in the figure, which arrow indicates the direction of the net force on the satellite?

1
2
3
4
5

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Q2: What is the difference in the force of gravity on a 1.0 kg mass at the bottom of the deepest ocean trench and that at the top of the highest mountain? Assume that g = 9.8 m/s² at sea level. The radius of the Earth at sea level is 6.37 ¥ 10⁶ m. The deepest trench is the Marianas Trench, south of Guam, which has a depth of 1.103 ¥ 10⁴ m below sea level. The highest mountain is Everest in Nepal, which has a height of 8.847 ¥ 10³ m above sea level. The difference is

0.061 N
0.0067 N
0.027 N
0.034 N
0.0062 N

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Q3: If the mass of the Earth is 6 ¥ 10²⁴ kg, the mass of the moon 7 ¥ 10²² kg, the radius of the moon's orbit 4 ¥ 10⁸ m, and the value of the gravitational constant 6.67 ¥ 10^-11 N.m²/kg², the force between the Earth and the moon is approximately

5 ¥ 10⁴ N
2 ¥ 10²⁰ N
3 ¥ 10⁵⁰ N
7 ¥ 10³⁰ N
3 ¥ 10²⁸ N

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Q4: If a planet has a mass twice that of the Earth and a radius four times that of the Earth, the ratio of the acceleration due to gravity on the planet to that on the Earth is

1/8
1/2
1/16
2
12

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Q5: When a falling meteor is at a distance of twice the Earth's radius (R_E = 6.436 ¥ 10⁶ m) from the surface of the Earth, its acceleration due to gravity is approximately

9.80 m/s²
4.90 m/s²
3.27 m/s²
2.45 m/s²
1.09 m/s²

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