# Help Physics

1. Jun 5, 2010

### ubaidvu

2. Charge is also said to be conserved. What does it mean? Explain.

3. When a car drives off a cliff, why does it rotate forward as it falls?

4. Why does a book sitting on a table never accelerate "spontaneously" in response to the trillions of inter-atomic forces acting within it?

5.Captain Planet' is somewhere between galaxies. When a gong sounds in a neighboring spaceship, Captain reacts to the sound. What is wrong with this scenario?

6. If you know the position vectors of a particle at two points along its path and also know the time it took to move from one point to the other, can you determine the particle's instantaneous velocity? Its average velocity? Explain

7.Steel will rapture if subjected to a shear stress of more that about 4.2 * 108 N/m2. What sideward force is necessary to shear a steel bolt 1 cm in diameter?

8. A table-tennis ball is thrown at a stationary bowling ball. The table-tennis ball makes a one-dimensional elastic collision and bounces back along the same line. After the collision, compared to the bowling ball, the table-tennis ball has (a) a larger magnitude of momentum and more kinetic energy (b) a smaller magnitude of momentum and more kinetic energy (c) a larger magnitude of momentum and less kinetic energy (d) a smaller magnitude of momentum and less kinetic energy (e) the same magnitude of momentum and the same kinetic energy..

2. Jun 5, 2010

### pgardn

This looks like a review for a final or part of a final. Do you have your attempts at the answers? OR do you want to take one question at a time and give your attempts?

3. Jun 5, 2010

### ubaidvu

And
1 . If earth were to spin faster about its axis your weigh would be less.If you were in rotating space habitat that increases its spin rate.Explian why the spining rate has opposite effect?

2.A planet has two moon the radius of moon I is r and the radius of moon II is 2r.explain the gravitational magnitude effect on the radius?
3. Two peoples are carrying a uniform wooden board that is 3.00m long and weighs 160N.If one person applies an upward force equal to 60N at 1 end at what point does other point lift the board.

4. Jun 5, 2010

### pgardn

So what do you think? Have you studied rotation?