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prisoha [69]
3 years ago
10

4. For a point charge, we derived an expression from Gauss’s law for the electric field a distance r away. You have a point char

ge of +2q centered in a conductive spherical shell of inner diameter a and outer diameter b. You place +8q on the spherical shell. Find the following: a. What is the electric field for rb?
Physics
1 answer:
IrinaVladis [17]3 years ago
8 0

Answer:

Explanation:

A point charge of +2q centered in a conductive spherical shell of inner diameter a and outer diameter b will induce - 2q charge on the inner surface and +2q charge on the outer surface of the shell. Since 8q charge has been added to the shell , this charge will reside on the outer surface of the shell. so total charge on the outer surface will be 10q.  At a point less than a , the electric field will be due to +2q charge situated at the centre . The electric field will be as follows

E = k .2q / r² for r < a

= 8kq/ a²

electric field at a point  r = a>b

total charge  lying inside is +2q - 2q = 0 . So in the thickness of the shell , electric field will be zero as total charge inside is nil.

For a point at r > b total charge inside is 2q-2q+10q = 10q , so electric field at r which is lying outside  the shell .

E = k 10 q / r² for r > b

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If the distance between two masses is tripled, the gravitational force between changes by a factor of
maw [93]

A. 1/9

Explanation:

The gravitational force between two objects is given by

F=G\frac{m_1 m_2}{r^2}

where

G is the gravitational constant

m1 and m2 are the two masses

r is the distance between the two masses

From the formula, we see that the magnitude of the force is inversely proportional to the square of the distance: therefore, if the distance is tripled (increased by a factor 3), the magnitude of the force changes by a factor

\frac{1}{r^2}=\frac{1}{3^2}=\frac{1}{9}

6 0
3 years ago
Read 2 more answers
Check all that apply. The magnetic force on the current-carrying wire is strongest when the current is parallel to the magnetic
dedylja [7]

Answer:

The direction of the magnetic force acting on a current-carrying wire in a uniform magnetic field is perpendicular to the direction of the field.

The direction of the magnetic force acting on a current-carrying wire in a uniform magnetic field is perpendicular to the direction of the current.

The magnetic force on the current-carrying wire is strongest when the current is perpendicular to the magnetic field lines.

Explanation:

The magnitude of the magnetic force exerted on a current-carrying wire due to a magnetic field is given by

F=ILB sin \theta (1)

where I is the current, L the length of the wire, B the strength of the magnetic field, \theta the angle between the direction of the field and the direction of the current.

Also, B, I and F in the formula are all perpendicular to each other. (2)

According to eq.(1), we see that the statement:

<em>"The magnetic force on the current-carrying wire is strongest when the current is perpendicular to the magnetic field lines.</em>"

is correct, because when the current is perpendicular to the magnetic field, \theta=90^{\circ}, sin \theta = 1 and the force is maximum.

Moreover, according to (2), we also see that the statements

<em>"The direction of the magnetic force acting on a current-carrying wire in a uniform magnetic field is perpendicular to the direction of the field. "</em>

<em>"The direction of the magnetic force acting on a current-carrying wire in a uniform magnetic field is perpendicular to the direction of the current. "</em>

because F (the force) is perpendicular to both the magnetic field and the current.

5 0
3 years ago
NEED HELP !!!!!
goblinko [34]

Answers with Explanations:

1. Answer: True

Explanation:

Muscle cramps happen especially during an <em>"intense workout."</em> The frequency of cramps is related to heat, thus it is important to<u> stay hydrated</u> all throughout the workout. Eating should be done<em> at least 2 to 3 hours</em> <em>prior to workout</em> because eating immediately before exercise leads to undigested food. Such kind of food causes cramps.

2. Answer: True

Explanation: Applying direct pressure immediately after the injury can help <em>decrease bleeding.</em> Blood loss results to <u>blood that is collected under the skin. </u>This turns into the color of blue or black, also known as "bruise." Decrease bleeding would then mean decrease bruising.

Applying pressure also <em>decreases swelling </em>because it restricts the blood flow and fluid from reaching into the injury.

3. Answer: False

Explanation: "Lordosis" refers to the body's<em> natural lordotic curve</em>. This is considered "normal." The excessive inward curve of the lumbar spine is called "hyperlordosis." This is commonly caused by<u> poor posture, lack of exercise, obesity and spinal conditions.</u>

4. Answer: False

Explanation: The mnemonic acronym "RICE" stands for<em> Rest, Ice, Compression</em><em> (not Cold)</em> and<em> Elevation</em>. This term is commonly used in First Aid and was introduced by Gabe Mirkin in 1978.

5. Answer: True

Explanation: Keeping the proper posture during exercise <u><em>prevents the body from encountering injuries</em></u>. It also ensures that the body is executing the exercise by<u> using the muscles properly.</u>

6. Answer: False

Explanation: "Ice" is important in<em> decreasing the swelling of the injury</em>. It constricts the blood vessels which prevents the flow of blood and other fluids towards the site of injury.

7. Answer: False

Explanation: The spine is naturally straight if a person doesn't have a medical problem. However, scoliosis is a medical problem. It is <u>a condition wherein a person's spine is </u><u>curved</u>, rather than being straight.

8. Answer: True

Explanation: When it comes to exercise,<em> starting slow</em> is the main key. It is followed by<u> gradual building up.</u> The increase will depend on the person's stamina. For example, <em>starting with a warm-up, followed by a slow walk then pacing up to a brisk walk.</em>

9. Answer: True

Explanation: Kyphosis is a spinal condition wherein the person's spine is <em>excessively curved outward.</em> This causes the upper back and the shoulders to be rounded. This condition is commonly called "hunchback."

10. Answer: True

Explanation: Proper posture entails the right amount of spinal curve. This means that the spine is in "neutral position." This means that the spine takes on the "S-shape." A little amount of curve results to a<em> "flat back</em>" while too much curve results to a <em>"swayback</em>."

11. Answer: all of the above

Explanation: Body posture and technique are important especially when it comes to exercise. Poor posture and technique lead to strain on joints, ligaments and injury especially to the muscles. This also puts the body out of alignment.

12. Answer: True

Explanation: Stretching is appropriately done at the<u> end of a warm-up</u> when the temperature has increased because at this time, the muscles are already flexible. It allows the muscles to be loosened and also aids in better performance during workouts or exercises.

13. Answer: False

Explanation: "Lifting" with your back only will result to muscle injury. There are several ways to do lifting such as "pull-ups" or "lat pull downs." This means that you are not lifting with your back only but using your other joints and muscles for lifting.

14. Answer: True

Explanation: "Warming-up" is an essential preparation before any workout because it prepares the body by<em> increasing temperature</em> and <em>blood flow to the muscles</em>. Without it, the muscles will become sore and the chance for injuries increases.

15. Answer: True

Explanation: "Cool down" is considered equally important as "warm-up." <u>It lowers the body's temperature </u>and lowers the amount of lactic acid that causes<u> muscle cramping, soreness and stiffness.</u>

16. Answer: True

Explanation: It is said that<em> most people forget about warming up and cooling down before and after they work out</em>. It is necessary to have 5 to 10 minutes of warm-up and cool down for every exercise routine.

17. Answer: False

Explanation: Knee extension is <em>best done at 90 degrees angle</em> as advised by most health experts. However, it depends on your capability and your exercise goals. For some people, <u>extending beyond 90 degrees is beneficial.</u>

18. Answer: True

Explanation: Tucking your belly button helps with your body's core exercise. If this is going to be done throughout the day, then surely it will strengthen the muscles. This can be done while a person is sitting down or walking.

4 0
3 years ago
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ser-zykov [4K]

Answer:A

Explanation:

Since the bucket of water  is constantly in motion it implies a force must be acting on it which allows it to change its Position constantly.

A constant gravity Force must be acting on water . In addition to gravity force a centripetal force must be acting on the water inside the bucket.

Bucket must move with certain velocity in order to avoid spilling of water.                    

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3 years ago
Isostatic rebound
svp [43]
I think it is B the rise of the land
4 0
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