Essay questions for dynamics: Laws of motion and gravitation

by Quirino Sugon Jr.

I.  Physical Laws.  State the following laws in one sentence.

1. Law of universal gravitation
2. Gauss’s law for gravitation
3. Newton’s first law of motion
4. Newton’s second law of motion
5. Newton’s third law of motion

II.  Application.  Answer the following questions in at most two sentences.

1. Why are there high tides and low tides?
2. If you drill a hole from the North Pole to the South Pole and you drop the stone on the hole, what will happen to the stone?  Describe its motion.
3. If you are in a supermarket and you wish to buy meat, how do you estimate the force constant of the spring in the weighing scale?
4. Are the geostationary satellites not moving?
5.  You are standing on  top of a weighing scale while in an elevator.  If the elevator’s cables snap and the elevator falls freely, what happens to your weight and mass?  Why?
6. How do you measure the mass of the earth?
7. How did Cavendish measure the gravitational constant?
8. What is dark matter and why do scientists believe such matter exist?

Identification questions for dynamics: Laws of motion, gravitation, rotations, and oscillations

by Quirino Sugon Jr.

Read Hewitt, 9th ed., Chapters 2, 3, 5 (Newton’s laws), 9 (Gravity), 10 (Projectile and Satellite Motion), 19 (Vibrations and Waves)

I.  Identification.  Identify the word or phrase described.  Write your answer on the space provided before each number.

1. A state when the net force acting on an object is zero
2. Push or pull
3. Property of things to resist changes in motion
4. Quantity of matter in an object
5. Force of gravity on an object
6. A law relating the intensity of an effect to the inverse square of the distance from the cause
7. a condition encountered in free fall wherein a support force is lacking
8. The influence that a massive body extends into space around itself, producing a force on another massive body.
9. A concentration of mass resulting from gravitational collapse, near which gravity is so intense that not even light can escape.
10. The primordial explosion that is thought to have resulted in the expanding universe
11. The speed that a projectile, space probe, or similar object must reach to escape the gravitational influence of the Earth or celestial body to which it is attracted.
12. Maximum displacement in a sinusoidal motion
13. Number of vibrations per unit time
14. Time for one complete oscillation

II.  Symbols.  Identify the symbol or group of symbols described.  Write your answer on the space provided before each number.

1. Force
2. Net force
3. Component of a force along the x-direction
4. Component of acceleration along the y-direction
5. Amplitude
6. Angular velocity
7. Frequency
8. Period
9. Phase angle
10. Unit for frequency
11. Unit for angular frequency
12. Gravitational constant
13. Unit for force equal to
14. Orbital radius
15. Volume
16. Volume of a sphere
17. Area of a circle
18. Surface area of a sphere
19. Product of the masses
20. Square of the distance
21. Force constant of a spring
22. Opposite