Exploring Balance, Charge, Rotation, Spontaneous Motion

[ubaidvu]

1. If you walk along the top of a fence, why does holding your arms out help you to keep your balance?



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..

 

[pgardn]

1. If you walk along the top of a fence, why does holding your arms out help you to keep your balance?



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..

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?

 

[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.

 

[pgardn]

1. If you walk along the top of a fence, why does holding your arms out help you to keep your balance?

So what do you think? Have you studied rotation?

 

[rdl]

1. Holding your arms out while walking on a fence helps you to keep your balance because it increases your overall mass, making it more difficult for external forces to disturb your center of gravity. This increased mass also provides more rotational inertia, making it easier to maintain your balance and prevent any sudden changes in direction.

2. Charge conservation means that the total amount of electric charge in a closed system remains constant. This means that charge cannot be created or destroyed, only transferred or redistributed. This principle is based on the law of conservation of energy, which states that energy cannot be created or destroyed, only transformed from one form to another.

3. When a car drives off a cliff, it rotates forward as it falls due to the principle of conservation of angular momentum. As the car falls, its center of mass moves in a straight line, but the rotation of the car around its center of mass creates an angular momentum that is conserved. This causes the car to rotate forward as it falls.

4. A book sitting on a table never accelerates spontaneously because of the principle of inertia. Objects at rest tend to stay at rest unless acted upon by an external force. In this case, the forces acting on the book are balanced, resulting in no net force and therefore no acceleration.

5. There are a few issues with this scenario. First, sound cannot travel through a vacuum, so Captain Planet would not be able to hear the gong in the neighboring spaceship. Additionally, even if there was a medium for sound to travel through, it would take a significant amount of time for the sound to reach Captain Planet's location, making it unlikely for him to react to the sound in real time. Finally, the concept of sound traveling through space is not scientifically accurate.

6. Yes, you can determine the particle's instantaneous velocity by dividing the displacement vector (the difference between the two position vectors) by the time it took to move from one point to the other. This will give you the average velocity over that time interval. To determine the instantaneous velocity, you would need to take the limit as the time interval approaches zero, essentially finding the slope of the displacement-time graph.

7. To shear a steel bolt 1 cm in diameter, a sideward force of 4.2 * 108 N would be necessary. This is calculated by multiplying the shear stress (4.2 * 108 N/m2) by the cross-sectional area of the bolt (πr2 = π