Answer:
Explanation:
Current density J = i / A where i is current and A is cross sectional area
J = 5 / π x ( .1 x 10⁻² )²
= 1.6 x 10⁶ A / m²
b )
electric field applied E = V / l where V is potential difference and l is lemgth of rod
E = 75 / 1.5
= 50 v / m
c )
J = σ E
J is current density , σ is conductivity and E is electric field .
1.6 x 10⁶ = σ x 50
σ = 3.2 x 10⁴ Ω⁻¹ m⁻¹
Resistivity = 1 / σ
= 1 / 3.2 x 10⁴
= .3125 x 10⁻⁴
=3.125 x 10⁻⁵ Ω m
Which of the following is an example of a primary source?
A. A dictionary definition of a science term
B. An article written by a scientist
C. A textbook written by a scientist
D. An encyclopedia entry about an experiment
Answer:
i think its no c.
a textbook written by a scientist. because its a first hand data.
An article written by a scientist is an example of a primary source. The correct option is option (B).
A primary source refers to an original, firsthand account or direct evidence of an event, topic, or research. It is created by individuals who directly participated in or witnessed the subject matter. An article written by a scientist would be considered a primary source as it typically presents the researcher's own observations, experiments, methodology, and conclusions.
It provides direct access to the original research and findings, making it an important source for scholarly and scientific purposes. In contrast, options A, C, and D are secondary sources that provide interpretations or summaries of information from primary sources.
Therefore, The correct option is an option (B).
To know more about the primary source:
https://brainly.com/question/24172115
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An object moving north with an initial velocity of 14 m/s accelerates 5 m/s2 for 20 seconds. What is the final velocity of the object? 39 m/s 90 m/s 114 m/s 414 m/s
Answer:
Final velocity of the object(v) = 114 m/s
Explanation:
Given:
Initial velocity (u) = 14 m/s
Accelerates (a) = 5 m/s²
Time taken = 20 seconds
Find:
Final velocity of the object(v) = ?
Computation:
According to 1st law of motion.
⇒ v = u +at
⇒ v = 14 + (5)(20)
⇒ v = 14 + 100
⇒ v = 114 m/s
Final velocity of the object(v) = 114 m/s
Rosa records the distance that a toy car rolls and the time it takes to cover the distance. What scientific practice is this? collecting data asking a question providing explanations communicating results
Answer:
collecting data
Explanation:
Data collection refers to a systematic method for gathering and analyzing information from a number of sources in order to provide a complete and reliable image of a subject region. The collection of data helps an individual or organization to answer specific questions, determine outcomes, and predicting future possibilities and outcomes. As per the question, rosa is collecting data about the distance and time of her toy car intrigued by the scientific query.
Answer:
A : Data
Explanation:
I’m doing the exam
Priscilla is driving her car on a busy street and Harvey passes her on his motorcycle. What will happen to the sound from his motorcycle after it
passes her car?
Answer:
what will happen to the sound is the wavelength increases thus frequency decreases so the sound decreases as he move away from her car..
20. Which of the following ray diagrams is correct?
Explanation:
The second one is the correct answer
Which option describes a phase change
Answer:
b. Gasloine evaporating into the air
I tryed to answer
A 51-kg woman runs up a vertical flight of stairs in 5.0 s. Her net upward displacement is 5.0 m. Approximately, what average power did the woman exert while she was running?
Answer:
The average power the woman exerts is 0.5 kW
Explanation:
We note that power, P = The rate at which work is done = Work/Time
Work = Energy
The total work done is the potential energy gained which is the energy due to vertical displacement
Given that the vertical displacement = 5.0 m, we have
Total work done = Potential energy gained = Mass, m × Acceleration due to gravity, g × Vertical height, h
m = 51 kg
g = Constant = 9.81 m/s²
h = 5.0 m
Also, time, t = 5.0 s
Total work done = 51 kg × 9.81 m/s²× 5 m = 2501.55 kg·m²/s² = 2501.55 J
P = 2501.55 J/(5 s) = 500.31 J/s = 500.31 W ≈ 500 W = 0.5 kW.
A 15.0 cm object is 12.0 cm from a convex mirror that has a focal length of -6.0 cm. What is the height of the image produced by the mirror? A. –5.0 cm B. 7.5 cm C. -7.5 cm D. 5.0 cm
Answer: D. 5cm
Explanation:
Given the following :
Focal length (f) = - 6.0 cm
Height of object = 15.0cm
Distance of object from mirror (u) = 12.0cm
Height of image produced by the mirror =?
Firstly, we calculate the distance of the image from the mirror.
Using the mirror formula
1/f = 1/u + 1/v
1/v = 1/f - 1/u
1/v = 1/-6 - 1/12
1/v = - 1/6 - 1/12
1/v = (- 2 - 1) / 12
1/v = - 3 / 12
v = 12 / - 3
v = - 4
Using the relation :
(Image height / object height) = (- image distance / object distance)
Image height / 15 = - (-4) / 12
Image height / 15 = 4 / 12
Image height = (15 × 4) / 12
Image height = 60 / 12
Image height = 5cm
Answer:
D. 5 cm
Explanation:got it right
A lens is used to make an image of magnification -1.50. The image is 30.0 cm from the lens. What is the object’s distance (unit=cm)? PLS HELP
Answer: 20cm
Explanation:
Given the following data:
Magnification of image = - 1.50
Distance of image from the lens = 30.0cm
The Magnification of an image is the ratio of the image distance from the lens and the object distance from the lens.
Mathematically,
Magnification(M) = - (image distance (di) / object distance (do))
M = - (di/do)
-1.50 = - (30/do)
do = 30 / 1.5
do = 20 cm
Object is placed at a distance of 20cm from the lens.
At which point does the planet have the least gravitational force acting on it?
Answer:
At which point does the planet have the least gravitational force acting on it?
Explanation:
In an elliptical orbit, when a planet is at its furthest point from the Sun, it is under the least amount of gravity, meaning that the force of gravity is strongest when it is closest.
Answer:
Point A
Explanation:
Recall that gravitational force is inversely proportional to the square of the distance between the 2 objects.
This means that the farther away the objects are from each other, the lesser their gravitational interaction will be.
In this case we can see that Point A is furthest away from the star, hence this will be the location with the least gravitational force from the star.
In general, the the string or air column of a musical instrument is, the more harmonics are generated.
Answer:
In general, the LONGER the string or air column of a musical instrument is, the more harmonics are generated.