A model rocket is shot directly upward, rises to its maximum height and then returns to its launch position in 10.0 s. Assuming
1 answer:
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1-2) They have same surface charge density
3-4) The metallic conductor has greatest surface charge density
Explanation:
1-2)
In a conductor, the charge carriers (mainly electrons) are free to move. Therefore, as a result, they tend to move at the largest possible distance from each other, because of the repulsive force that they exert on each other.
The configuration that maximize the distance between the charge carriers for a solid sphere of metallic conductor is the one in which all the electrons are on the surface, and they are equally spaced between each other. This means that for the solid sphere of radius R, the excess charge Q will be entirely spread over the surface of the sphere.
Similarly, the excess charge Q on the hollow spherical shell (which is also made of the same conducting material) will also be spread over the surface with the charge carriers at the maximum distance from each other. Therefore, the surface charge density for both objects will be
where R is the radius of the two spheres.
3-4)
In this case, the surface charge density on the two objects is different.
In fact, on the metallic sphere (conducting) the surface charge density is (as explained in part 1):
Hoever, the second sphere is made of an insulating material. In an insulator, the charge carriers are not free to move. If the initial charge Q is spread across the all sphere (which is not hollow), this means that some of the charge will actually also be inside the sphere. So the charge deposited on the surface, Q', will be less than the total charge Q. Therefore, the surface charge density will be
And since Q' < Q, this means that , so the conducting sphere has a greatest surface charge density.
Answer:
The impact occured at a distance of 2478.585 meters from the person.
Explanation:
(After some research on web, we conclude that problem is not incomplete) The element "Part A" may lead to the false idea that question is incomplete. Correct form is presented below:
<em>A person, with his ear to the ground, sees a huge stone strike the concrete pavement. A moment later two sounds are heard from the impact: one travels in the air and the other in the concrete, and they are 6.4 seconds apart. How far away did the impact occur? (Sound speed in the air: 343 meters per second, sound speed in concrete: 3000 meters per second)</em>
Sound is a manifestation of mechanical waves, which needs a medium to propagate themselves. Depending on the material, sound will take more or less time to travel a given distance. From statement, we know this time difference between air and concrete (), in seconds:
(1)
Where:
- Time spent by the sound in concrete, in seconds.
- Time spent by the sound in the air, in seconds.
By suposing that sound travels the same distance and at constant speed in both materials, we have the following expression:
(2)
Where:
- Speed of the sound in concrete, in meters per second.
- Speed of the sound in the air, in meters per second.
- Distance traveled by the sound, in meters.
If we know that ,
and
, then the distance travelled by the sound is:
The impact occured at a distance of 2478.585 meters from the person.
Answer: The wheel's average rotational acceleration is -0.4 radians per second squared (rad/s^2)
Explanation: Please see the attachments below
