Nine elements that have been known since ancient times, and their discovery dates are not precisely recorded are Gold (Au), Silver (Ag), Copper (Cu), Iron (Fe), Lead (Pb), Tin (Sn), Mercury (Hg), Sulphur (S) and Carbon (C).
1. Gold (Au): Gold has been used by humans for thousands of years, with evidence of its use dating back to ancient civilizations like the Egyptians, Sumerians, and Indus Valley people.
2. Silver (Ag): Like gold, silver has a long history of human use and has been mined and utilized for various purposes since ancient times.
3. Copper (Cu): Copper is one of the oldest metals known to humans, and its use dates back over 10,000 years. It was one of the first metals to be smelted and used in tools, weapons, and art.
4. Iron (Fe): Iron is another ancient element that has been used for thousands of years. Early civilizations discovered iron in meteorites and later learned to smelt it from iron ores.
5. Lead (Pb): Lead has been known to humans since ancient times and was used by the ancient Egyptians, Greeks, and Romans. It was widely used in plumbing, as well as for making containers and pigments.
6. Tin (Sn): Tin has been used by humans for thousands of years, mainly in the form of an alloy called bronze (copper-tin alloy), which was crucial for the Bronze Age.
7. Mercury (Hg): Mercury has a long history of use in various cultures for medicinal, alchemical, and decorative purposes.
8. Sulphur (S): Sulfur has been used since ancient times for various purposes, including medicine, bleaching, and as a component in sulfuric acid production.
9. Carbon (C): While the element carbon itself has always existed on Earth, the awareness of its presence and significance as an element is ancient.
These elements were used by ancient civilizations for various purposes such as jewelry, tools, construction, and religious rituals. Their discovery dates are lost in antiquity, as they have been known to humans for thousands of years.
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Can you please answer my question correctly ASAP
Answer:
1) C, 2) C, 3) B, 4) D, 5) A/B, 6) D, 7) D, 8) A, 9) B, 10) A
Explanation:
1) Seconds, minutes and days are time units. (Correct answer: C)
2) The displacement is shortest distance between the point of origin and the point of destination. (Correct answer: C)
3) The velocity is the rate of change of position in time. (Correct answer: B)
4) Graphs are a very useful ressource to infer characteristics inherent to a studied physical variable. (Correct answer: D)
5) There are two possible answers, since both milimeters and meters are units for distance. (Correct answers: A/B)
6) The distance is the arc length of the entire path that object travelled. (Answer: D)
7) Traditionally, in a position vs. time graph we plot time in the x-axis. (Answer: D)
8) In this case, we use a distance-time graph, where travelled distance is the dependent variable and time is the independent variable. (Answer: A)
9) The point of origin is the initial position of the object. (Answer: B)
10) The point of destination is the final position of the object. (Answer: A)
A man lifts a 5 Newton bag of groceries
from the floor to the top of the countertop,
which is 1.1 meters tall. What is the work
done by this person in lifting groceries?
5
5.5
4.5
6
A small block with mass 0.0350 kgkg slides in a vertical circle of radius 0.550 mm on the inside of a circular track. During one of the revolutions of the block, when the block is at the bottom of its path, point AA, the magnitude of the normal force exerted on the block by the track has magnitude 3.90 NN . In this same revolution, when the block reaches the top of its path, point BB, the magnitude of the normal force exerted on the block has magnitude 0.670 NN . Part A How much work was done on the block by friction during the motion of the block from point AA to point BB
Answer:
W_net = μ 5.58, μ = 0.1 W_net = 0.558 J
Explanation:
The work is defined by the related
W = F. d = F d cos θ
where bold indicates vectors.
In the case, the work of the friction force on a circular surface is requested.
The expression for the friction force is
fr = μ N
the friction force opposes the movement, therefore the angle is 180º and the cos 180 = -1
W = - fr d
the path traveled half the length of the circle
L = 2 π R
d = L / 2
d = π R
we substitute
W = - μ N d
Total work is initial to
W_neto = - μ π R (N_b - N_a)
let's calculate
W_net = - μ π 0.550 (0.670 - 3.90)
W_net = μ 5.58
for the complete calculation it is necessary to know the friction coefficient, if we assume that μ = 0.1
W_net = 0.1 5.58
W_net = 0.558 J
Which of the following refers to the concentration of a substance?
A.the maximum amount of a solute that can be dissolved in a solvent at a given temperature
B.the minimum volume of solvent dissolved per liter of solution at a given pressure
C.the grams of solute dissolved per 100 g of solvent
D.the size of the particles that make up a substance
The statement which refers to the concentration of a substance is the maximum amount of a solute that can be dissolved in a solvent at a given temperature. Thus, the correct option for this question is A.
What is a Substance?A substance may be defined as a type of chemical element and its compounds in the natural state or the result of a manufacturing process. In a manufacturing process, a chemical reaction is usually required in order to form a substance.
The concentration of a substance is the quantity of solute present in a given quantity of solution. Concentrations are usually expressed in terms of molarity, defined as the number of moles of solute in 1 L of solution.
Therefore, the maximum amount of a solute that can be dissolved in a solvent at a given temperature is a statement that refers to the concentration of a substance. Thus, the correct option for this question is A.
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Water tends to moderate climate. Why is it warmer in the winter and cooler in the summer in cities located near the ocean or large lakes?
A.Water has a low specific heat and therefore changes temperature faster than most other substances.
B.Water has a low specific heat and therefore changes temperature slower than most other substances.
C.Water has a high specific heat and therefore changes temperature more slowly than most other substances.
D.Water has a high specific heat and therefore changes temperature more quickly than most other substances.
It is warmer in the winter and cooler in the summer in cities because water has high specific heat and therefore changes temperature more slowly than most other substances. The correct option is C.
What is climate?Climate is the average weather over a longer period of time in a particular area. A description of a climate includes details such as the typical temperature in each season, the amount of rainfall, and the amount of sunshine.
Coastal weather tends to be more moderate than continental weather, with fewer hot and cold extremes, because the ocean warms and cools more slowly than the atmosphere.
The majority of rain clouds are produced by ocean evaporation, particularly in the tropics, which affects where wet and dry regions on land are located.
Therefore, the correct option is C. Water has a high specific heat and therefore changes temperature more slowly than most other substances.
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What does the object below model?
O A. The heart
O B. The skeletal system
C. The brain
O D. The lungs
Answer: c
Explanation: it is c because i used my brain to answer it
Answer: The Brain
Explanation:
Its the brain
Determine whether a moving tennis ball and a racket held by the player have the same momentum or different momentum. If different, determine which object has more momentum.
Answer:
key points:1.momentum and impulse
2.condition for conservation of momentum and why
3.how to solve collision problems
4.centre of mass
Explanation:
momentum is a vector
force of a tennis ball
for a top player,a tennis ball may leave the racket on the with a speed of 55m/s(about 120mi/h).if the ball has a mass of 0.060kg and is in contact with the racket for about 4ms(4×10)s.estimate the average force on the ball
A piece of steel is 11.5cm long at 22C. It is heated to 1221C, close to its melting point. How long is it, in cm, at the high temperature?
Answer:
The length at the final temperature is 11.7 cm.
Explanation:
We need to use the thermal expansion equation:
[tex]\Delta L=\alpha L_{0}\Delta T[/tex]
Where:
L(0) is the initial lengthΔT is the differential temperature, final temperature minus initial temperature (T(f)-T(0))ΔL is the final length minus the initial length (L(f)-L(0))α is the coefficient of linear expantion of steel (12.5*10⁻⁶ 1/°C)So, we have:
[tex]L_{f}-L_{0}=\alpha L_{0}(T_{f}-T_{0})[/tex]
[tex]L_{f}=L_{0}+\alpha L_{0}(T_{f}-T_{0})[/tex]
[tex]L_{f}=0.115+(12.5*10^{-6})(0.115)(1221-22)[/tex]
[tex]L_{f}=0.117\: m[/tex]
Therefore, the length at the final temperature is 11.7 cm.
I hope it helps you!
The mineral quartz has a chemical formula of SiO2. What is the formal name
for this compound?
Answer:
Silicon Dioxide
Answer:
Silicon dioxide
Explanation:
What is the average speed of a car that travelled 400 miles in 6 hours?
Answer:
About 66 miles per hour
Explanation:
Based on the information given we can assume the car traveled the same number of miles every hour meaning all we need to do is divide.
400/6 ≈ 66 miles per hour
Answer
66 mph
Explanation:
400 ÷ 6 = 66.666666666666666.......
what two factors directly affect the acceleration of an object?
The acceleration of an object depends on the mass of the object and the amount of the force applied to it. It states that the acceleration of an object increases with increased force and decreases with increased mass.
Help pls sand quickly plssssss
Answer:
The magnet produces an electric current in the wire
Explanation:
Answer: the first one is right
Explanation:
A student holds an ice cube in her hand. Which of the following best describes the movement of heat that will happen?
Answer:
The ice will melt and her hand will get cold
Explanation:
an electric bulb is marked 40volts ,230w another bulb is marked 40w,110v
a.calculate the ratio of their resistance
b.the ratio of their energy
c.find the charge on each bulb
d.which of the two bulbs can hold enough .
Answer:
a. The ratio of their resistance is 2783:64
b. The ratio of their energy is 4:23
c. The charge on the first bulb is 5.75 C
The charge on the second bulb is [tex]0.\overline {36}[/tex] C
Explanation:
The voltage on one of the electric bulbs, V₁ = 40 volts
The power rating of the bulb, P₁ = 230 w
The voltage on the other electric bulbs, V₂ = 110 volts
The power rating of the bulb, P₂ = 40 w
a. The power is given by the formula, P = I·V = V²/R
Therefore, R = V²/P
For the first bulb, the resistance, R₁ = 40²/230 ≈ 6.96
The resistance of the second bulb, R₂ = 110²/40
The ratio of their resistance, R₂/R₁ = (110²/40)/(40²/230) = 2783/64
∴ The ratio of their resistance, R₂:R₁ = 2783:64
b. The energy of a bulb, E = t × P
Where;
t = The time in which the bulb is powered on
∴ The energy of the first bulb, E₁ = 230 w × t
The energy of the second bulb, E₂ = 40 w × t
The ratio of their energy, E₂/E₁ = (40 w × t)/(230 w × t) = 4/23
∴ The ratio of their energy, E₂:E₁ = 4:23
c. The charge on a bulb, 'Q', is given by the formula, Q = I × t
Where;
I = The current flowing through the bulb
From P = I·V, we get;
I = P/V
For the first bulb, the current, I = 230 w/40 V = 5.75 amperes
The charge on the first bulb per second (t = 1) is therefore;
Q₁ = 5.75 A × 1 s = 5.75 C
The charge on the first bulb, Q₁ = 5.75 C
Similarly, the charge on the second bulb, Q₂ = (40 W/110 V) × 1 s = [tex]0.\overline {36}[/tex] C
The charge on the second bulb, Q₂ = [tex]0.\overline {36}[/tex] C.
d. The question has left out parts
7. A jogger runs three blocks south, two blocks east, 4 blocks north and
two blocks west. What is the DISTANCE the jogger ran? *
Answer:
11 blocks
Explanation:
distance is adding up the numbers while displacement is the difference in starting and ending points
An object is pulled northward at 20 N and southward at 15 N. What is the direction and force of the object?
Answer:
It moves northward at 5N
Explanation:
BRAINLIEST TO THE CORRECT QUESTION
Answer:
the answer is B
visible light
Which of the following are devices that utilize electromagnets? Select all that apply?
relay switches
doorbells
crane pulleys
security locks
NO LINKS!!!!!! Help its urgent, PLEASE HELP!!!!!!!!!!!!!!!!
Answer:
I think ur answer would be B
Explanation:
srry if wrong
hope this helps
The distance between two subway stations is 3 miles. If a train travels between the two stations at an average speed of 60 mph, how many minutes does it take for the train to finish the trip between the two stations?
Answer:3 minutes
Explanation:60 miles an hour, 60 minutes in an hour, 1 mile per minute
A skateboarder is traveling at a velocity of 8 m/s. She slows down and comes to a stop in 4 seconds. Calculate the skater’s acceleration.
Answer:
Go to this link it has many examples - https://staff.retsd.mb.ca/public/or4xe53elrzxg5ldmjuwe3i/Lists/SharedDocuments/Physics/14.2.PDF
Explanation:
Link ^
Help it is timed help
Answer:
It is an object that remains a magnet forever.
Explanation:
a bed that has an area of 3.75 m2 and weighs 1,025N, what pressure would the bed exert on the floor?
Answer:
0.03964
Explanation:
Let us calculate the pressure exerted on the bottom by the weight of the fluid. That pressure is the weight of the fluid mg divided by the area A supporting it (the area of the bottom of the container): P=mgA P = mg A.
A girl runs 40m due south in 40 seconds an d then 20m due north in 10 secondsCalculate.
the average speed,
her average velocity .
in her change in velocity for the whole journey!
The average speed of the girl is 1.2 m/s.
Average velocity is defined as the trade in position or displacement (∆x) divided by the time durations (∆t) wherein the displacement takes place. The common velocity can be effective or negative depending upon the sign of the displacement. The SI unit of average velocity is meters per second (m/s or ms-1).
Given;
Total distance = 40 + 20 = 60 M
Displacement = 40 - 20 = 20 m south
total time = 40 + 10 = 50 seconds
Average speed = total distance / total time
= 60/50
= 1.2 m/s
average velocity = total displacement / total time
= 20 / 50
= 0.4 m/s due south.
Average velocity is calculated by means of dividing your displacement (a vector pointing out of your initial role in your final position) through the entire time; the average pace is calculated by way of dividing the overall distance you traveled by means of the total time.
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Calculate frequency if wavelength is 35 m and wave speed is 546 m/s.
25.6 Hz
15.6 Hz
390 Hz
.06 Hz
how to do this please
Answer:
1) see the diagram below
2) (b) the length of the wire being tested
Explanation:
1) An ammeter is connected in series with the circuit branch in which you want to measure current. "Conventional current" enters the positive terminal of the ammeter. (You can think of it as a voltmeter across a small resistor. The polarity of the voltage matches the polarity of the current.)
A voltmeter is connected in parallel with the circuit element of interest. Here, you want to measure the voltage across the wire, so the voltmeter is placed in parallel with the wire. The positive terminal of the voltmeter is connected to the end of the circuit element that has the higher (more positive) potential.
__
2) The wording of the problem tells you which variable is independent:
"A varies with B" means the independent variable is B
Here, the independent variable is the length of the wire.
A chocolate bar has nutritional energy content of 100KJ. If an 50kg mountain climber eats this chocolate bar and converts it all to potential energy. What altitude(height) can she climb on a mountain using this energy? Consider g=10m/s^2
Answer:
h = 200 m
Explanation:
The energy content of the chocolate is completely converted to the potential energy of the climber. Therefore:
[tex]Energy\ of\ Chocolate = Potential\ Energy\\Energy\ of\ Chocolate = mgh[/tex]
where,
m = mass of climber = 50 kg
Energy of Chocolate = 100 KJ = 100000 J
g = acceleration due to gravity = 10 m/s²
h = height = ?
Therefore,
[tex]100000\ J = (50\ kg)(10\ m/s^2)h\\\\h = \frac{100000\ J}{500\ N}[/tex]
h = 200 m
Consider two soap bubbles having radii r1 and r2 (r1 < r2) connected via a valve. What happens if we open the valve?
Answer:
Explanation:
The radius of the smaller bubble, r1 will decrease and that of the bigger bubble, r2 will increase.
The pressure that is present in the smaller bubble usually is greater than the pressure that exists inside that of the bigger bubble. This then makes air to flow from r1 to r2 thereby making the radius of the smaller bubble r1, to decrease while keeping that of the bigger bubble r2 higher.
2. Why is alcohol thermometer not suitable to measure high temperature?
Answer:
Alcohol thermometers are used rather than mercury thermometers in very cold regions because alcohol has a lower freezing point than mercury. Pure ethanol freezes at -115 degrees C, while mercury freezes at -38 degrees C.
Explanation:
It is less durable because alcohol evaporates faster than mercury. It cannot measure high temperature because of a low boiling point. It wets the walls of the thermometer, which can adversely impact the accuracy of readings
4. An automobile gasoline engine is able to do 225 J of useful work with each stroke of its
pistons. If the engine has an efficiency of 29%, what is the amount of work that must be done on
the pistons in the engine?
[tex]\mathfrak{\huge{\orange{\underline{\underline{AnSwEr:-}}}}}[/tex]
Actually Welcome to the concept of Efficiency.
We know that, efficiency is given as,
E (eta) = Output work / Input Work
hence, here, E = 29% and Output work = 225
hence, 29% = 29/100 in real..
hence, the work done on piston is given as,
29/100 = 225/I
therefore, I = 225*100/29 ==> I = 22500/29 ==> I = 775.8 joules
hence, the work done on the pistons is 775 J