Physics Module 3

Module: 3- A: Chapter Questions:

Read the chapter and answer these questions on your own

Chapter - 7. Energy:

1) Define Work and Power. What are their units?

2) What is the difference between Kinetic Energy and Potential energy? Give an example

3) Describe the Conservation of Energy by a circus diver example.

4) What are the similarities and differences between the Kinetic Energy and Momentum?

Chapter - 8. Rotational Motion:

1) Define the relationship between Rotational speed and Tangential speed

2) What is torque?

3) What is center of mass and center of gravity? Are they the same point or different points?

4) What is the difference between Centripetal Force and centrifugal force?

5) Define Angular Momentum. Give an example of Conservation of Angular Momentum

Chapter - 9. Gravity:

1) Why the Gravity is called the Universal law of Gravitation?

2) Write down the Gravitational Force equation.

3) What is the value of the Universal Gravitational Constant (G)?

4) How did Professor Cavendish measure the value of G first?

Used two spheres attached to end rode and a thin wire suspending the rod.

5) Define the Inverse Square Law of Gravity and Distance.

6) Explain why the Ocean tide is influenced more by the moon than by the sun.

Distance of moon to earth is lesser as compared to that of sun.

Chapter - 10. Projectile and Satellite Motion:

1) What is a Projectile motion? Give two examples

2) What is the velocity of a Satellite that can keep it in the Earth’s orbits without hitting the ground or escaping away from the earth?

3) What is the value of escape velocity?

4) Why the Satellite stays in orbit for such a long time without heading towards the earth?

5) Define Kepler’s three Laws of Planetary Motion

Module: 3- B: Chapter Exercises:

Exercise questions are at the end of each chapter. Answer these in details

Chapters/Topics Exercise#

7. Energy 2, 7, 25, 37, 53

2. Why do you do no work on a 25- kg backpack when you walk a horizontal distance of 100 mm?

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7. The Sun puts out twice as much solar energy in 2 hours as it does in 1 hour. But the solar power of the Sun is the same from one hour to the next. Distinguish between the terms solar energy and solar power.

25. Someone wanting to sell you a Superball claims that it will bounce to a height greater than the height from which it is dropped. Can this be?

37. What famous equation describes the relationship between mass and energy?

53. If two objects have equal kinetic energies, do they necessarily have the same momentum? Defend your answer.

8. Rotational Motion 1, 3, 4, 30, 59

1. While riding on a carnival Ferris wheel, Sam Nasty horses around and climbs out of his chair and along the spoke so he is halfway to the axis. How does his rotational speed compare with that of his friends who remain in the chair? How does his tangential speed compare? Why are your answers different?

3. A large wheel is coupled to a wheel with half the diameter, as shown. How does the rotational speed of the smaller wheel compare with that of the larger wheel? How do the tangential speeds at the rims compare ( assuming the belt doesn’t slip)?

4. Dan and Sue cycle at the same speed. The tires on Dan’s bike are larger in diameter than those on Sue’s bike. Which wheels, if either, have the greater rotational speed?

30. Nobody at the playground wants to play with the obnoxious boy, so he fashions a seesaw as shown so he can play by himself. Explain how this is done.

59. We believe that our galaxy was formed from a huge cloud of gas. The original cloud was far larger than the present size of the galaxy, was more or less spherical,

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9. Gravity 3, 13, 24, 34, 47

3. What would be the path of the Moon if somehow all gravitational forces on it vanished to zero?

13. Larry weighs 300 N at the surface of Earth. What is the weight of Earth in the gravitational field of Larry?

24. Why do the passengers in high- altitude jet planes feel the sensation of weight while passengers in an orbiting space vehicle, such as a space shuttle, do not?

34. If the mass of Earth increased, your weight would correspondingly increase. But, if the mass of the Sun increased, your weight would not be affected at all. Why?

10. Projectile & Satellite Motion 2, 7, 17, 30, 55

2. Suppose you roll a ball off a tabletop. Will the time to hit the floor depend on the speed of the ball? ( Will a fast ball take a longer time to hit the floor?) Defend your answer.

7. Fragments of fireworks beautifully illuminate the night sky. ( a) What specific path is ideally traced by each fragment? ( b) What paths would the fragments trace in a gravity- free region?

17. The hang time of a basketball player who jumps a vertical distance of 2 feet ( 0.6 m) is about What will be the hang time if the player reaches the same height while jumping 4 feet ( 1.2 m) horizontally?

30. Why are satellites normally sent into orbit by firing them in an easterly direction, the direction in which Earth spins?

55. Which requires less fuel, launching a rocket to escape speed from the Moon or from Earth? Defend your answer.