Answer: C
1054 g
Explanation:
Given that the object is in the shape of semi sphere with diameter of 8.2cm. And density of 7.3g/cm^3.
From definition of density,
Density = mass/volume
Volume of a half - sphere = 2/3πr^3
Volume = 2/3 × 3.143 × 4.1^3
Volume = 144.35 cm^3
Let make mass the subject of formula
Mass = Density × volume
Mass = 7.3 × 144.35
Mass = 1053.74g
The mass of the paperweight, in grams is 1054
Which of the organisms listed below can be considered a pest?
a
fungi
b
insects
c
bacteria
d
rodents
e
all of the above
Answer:
d
Explanation:
rodents example the house mouse gnaw and spoil food stored by humans this they are considered as pests
Final answer:
All the listed organisms, including fungi, insects, bacteria, and rodents can be considered pests in various contexts, such as when they cause harm to agriculture, food storage, or health.
Explanation:
When assessing which of the organisms listed can be considered a pest, it is indeed correct to consider all of the above as potential pests. This includes fungi, insects, bacteria, and rodents. For example, fungi can cause diseases in plants (like the stem rust on barley), leading to significant agricultural damage. Insects can also be pests, such as locusts that destroy crops or mosquitoes that spread diseases.
Bacteria are often responsible for food spoilage or plant diseases. Rodents, such as mice and rats, can contaminate food supplies and are known carriers of various diseases. These organisms can all be considered pests depending on the context, such as when they cause harm to human endeavors like agriculture, food storage, or human health.
Sound is an example of ?
a. a longitudinal wave.
b. a wave that can travel through a vacuum.
c. a transverse wave.
d. a wave that does not transmit energy.
Sound is a longitudinal wave, where the particles vibrate back and forth in the direction the wave is moving. It cannot travel in a vacuum as there are no particles to transmit the wave.
Explanation:Sound is an example of a longitudinal wave. This is because, in a longitudinal wave, the motion of the particles in the wave is in the same direction as the motion of the wave itself. When you speak for example, your voice creates a sound wave which makes the particles in the air vibrate back and forth in the same direction as the sound is traveling. On the contrary, transverse waves have particles that vibrate at a right angle to the direction of the wave, and the propagation of sound is not possible in vacuum (space devoid of matter) as there are no particles to vibrate and transmit the sound wave.
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Whose contributions to astronomy explained how planets were held in their orbits?
A. Aristotle
B. Copernicus
C. Ptolemy
D. Newton
E. Brahe
F. Kepler
Answer:
D newton
Explanation:
he did extensive research on gravity, and gravity is what holds planets in orbits.
The Earth orbits the sun with a speed of about 67000 miles per hour. If the Earth was to suddenly stop, it would
Answer: It would destroy the Earth's surface.
I remember reading this questions in What If? by Randall Munroe. Great book, I suggest you check it out. Anyway, the answer. The Earth is revolving as well as spinning on its axis at the same time. This basically means that thee atmosphere is also spinning at the same speed. But due to the frame of reference, we don't notice anything. If the Earth suddenly stops spinning, then the atmosphere, going according to the first law of motion will still be spinning at the same speed. This would produce supersonic winds at such a scale that it will be compared to an atomic explosion. Anything not in a nuclear bunker will probably be ripped apart by the force of the wind.
3. What is the charge on the leaves of an electroscope if a positively charged rod is moved near the
top of the electroscope? *
(10 Points)
A)Positive
B)Neutral
C)Negative
Which equations represent the relationship between wavelength and frequency for a sound wave? Check all that apply.
v = lambdaf
A = vf
f = v
A = StartFraction v over f EndFraction.
A = StartFraction f over v EndFraction.
f = StartFraction v over f EndFraction.
f = StartFraction lambda over v EndFraction.
Answer:
A,D,F
Explanation:
The equations that represent the relationship between wavelength and frequency for a sound wave are:
v = lambdaf
A = StartFraction v over f EndFraction.
f = StartFraction v over f EndFraction.
What are Frequency and Wavelength?Frequency and wavelength are inversely proportional to every other. The wave with the greatest frequency has the shortest wavelength. two times the frequency manner one-1/2 the wavelength, for this reason, the wavelength ratio is the inverse of the frequency ratio.
In physics, the wavelength is the spatial period of a periodic wave—the space over which the wave's shape repeats. It's far the gap between consecutive corresponding factors of the same phase at the wave, including two adjacent crests, troughs, or zero-crossings, and is a function of each journeying wave and standing waves, as well as other spatial wave styles.
The inverse of the wavelength is called the spatial frequency. Wavelength is normally unique with the aid of the Greek letter lambda (λ). The term wavelength is also every now and then implemented to modulated waves, and to the sinusoidal envelopes of modulated waves or waves shaped via interference of numerous sinusoids.
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Which of the following is NOT part of Earth’s biosphere?
1.Pacific Ocean
2.the Moon
3.Rocky Mountains
4.Cuba
Answer: The moon
Explanation: the moon is not on the earth
Earth's biosphere consists of the Pacific Ocean, Rocky Mountains, and Cuba (country), hence the moon is not part of the biosphere, so option 2 is correct.
What is a biosphere?The biosphere is a relatively narrow layer of the Earth's surface that supports life. It starts a few kilometers up in the atmosphere and ends at the deep ocean vents. The biosphere is a vast ecosystem made up of biotic (living things) and abiotic (nonliving) components, from which living things (biota) get their energy and nutrition.
Earth was a barren planet with shallow seas and a thin band of gases before life appeared there. These gases were primarily carbon dioxide, carbon monoxide, molecular nitrogen, hydrogen sulfide, and water vapor. The planet was hostile and desolate. The lithosphere (rock and soil), hydrosphere (water), and atmosphere make up this entirely inorganic state of Earth, which is known as the geosphere (the air).
Therefore, Earth's biosphere consists of the Pacific Ocean, Rocky Mountains, and Cuba (country).
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Which of the following is NOT an appropriate acceleration unit?
A)year/day/mile
B)meter/sec/sec
C)mile/hour/sec
D)centimeter/sec/year
Answer:a
Explanation:
A serving of french fries
releases 320 kcal (1 kcal =
4.18 kJ) when digested by your
body. If this same amount of
energy were transferred to 1.5
kg of water at 30°C, what
would the final temperature
Answer:
Explanation:
320 k Cal = 320 x 4.18 k J
= 1337.6 kJ
For rise in temperature the formula is
Q = m s Δ T
Q is heat added , m is mass of the water to which heat is added , s is specific heat of water , Δ T is rise in temperature .
1337.6 x 10³ = 1.5 x 4.18 x 10³ x Δ T ( specific heat of water is 4.18 kJ per kg.)
ΔT is more than 70 degree . That means , heat is sufficient to boil it .
So final temperature will be 100 degree Celsius.
What type of magnetism is present in a bar magnet?
A. Superconducting
B. Contact
C. Induced
D. Permanent
Answer:
It is made up of iron, steel or any other ferromagnetic substance or ferromagnetic composite, having permanent magnetic properties. The magnet has two poles: a north and a south pole. When you suspend it freely, the magnet aligns itself so that the north pole points towards the magnetic north pole of the earth.
The type of magnetism present in a bar magnet is permanent. The correct option is D.
What is magnet?A substance which is negative charged at one end and positive charged at another end creating the magnetic field around it.
A bar magnet also has magnetic fields around it. In the presence of magnetic force fields, any magnetic object will be attracted to it.
It is made up of iron or steel or any other ferromagnetic substance which have permanent magnet properties.
The magnet has two poles: a north and a south pole. When you suspend it freely, the magnet aligns itself so that the north pole points towards the magnetic north pole of the earth.
So, the type of magnetism present in a bar magnet is permanent.
Thus, the correct option is D.
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In the illustration above the moon is in the position called
new moon
moonstone
full moon
bright moon
Answer:
new moon
Explanation:
The new moon is the first lunar phase and is seen as a thin waxing crescent and its shape is formed the direct sunlight as viewed from the earth and stays form 6 am to 6 pm. It varies slightly due to its elliptical orbit and these phases are due to the angles from were the observer can see the moon illumination by the sun as it orbits the planet and the moon reflects the light received from the sun.What are the four types of musical instruments and what are the physical behind each type of musical instrument
Answer:
The four types of musical instruments are percussion, woodwind, brass, and strings.
Explanation:
Percussion instruments include drums, triangle, cymbals, and xylophones. There are more instruments than what i've mentioned though. Percussion instruments often produce the beat of songs.
Woodwind instruments include clarinets, oboe, flute, and saxophone. Woodwind instruments often produce the harmony of songs and, occasionally, the melody.
Brass instruments include trumpet, trombone, french horn, and tuba. Brass instruments often produce the harmony of songs, the trumpet produces the melody a lot though.
String instruments include guitars, violins, cello, bass, ukulele, and banjo. String instruments produce both the harmony and the melody. These instruments often produce really beautiful music, in my opinion.
The four types of musical instruments are aerophones, chordophones, membranophones, and idiophones.
Explanation:The four types of musical instruments are:
Aerophones (wind instruments): These instruments create sound by using air as the main component. Examples include flute, trumpet, and saxophone.
Chordophones (stringed instruments): These instruments produce sound by vibrating strings. Examples include guitar, violin, and piano.
Membranophones (instruments with a membrane): These instruments create sound by using a vibrating membrane. Examples include drums and tambourines.
Idiophones (self-sounding instruments): These instruments produce sound through their own vibrations. Examples include xylophone, maracas, and cymbals.
The molecules on pathogens that enable the immune system to distinguish one kind of pathogen from another are called _____.
T molecules
B molecules
antibodies
antigens
Answer:
I think the answer would be antigens
Explanation:
ASAP pls will mark brainiest
The general formula for an acid is
Answer:
To write the general formula for an acid, we fix one atom which is hydrogen because this atom is common to all the acids. General formula for acid is written by HX. where H represents Hydrogen atom.
Explanation:
The general formula for an acid is HA, where 'H' represents a hydrogen ion and 'A' is the conjugate base after the proton donation. Acid-base reactions follow the general equation of acid + base
ightarrow salt + water, and acids react with metals to form a salt and hydrogen gas.
The general formula for an acid in chemistry can be written as HA, where 'H' represents a hydrogen ion that can be donated, and 'A' represents the remainder of the acid molecule that forms the conjugate base after the acid donates its proton. When an acid reacts, such as in an acid-base reaction, it follows the equation acid + base → salt + water, which for a reaction with a metal hydroxide specifically becomes acid + metal hydroxide → salt + water. In the reaction of an acid with a pure metal, the general word equation is: acid + metal → salt + hydrogen gas. The type of salt and the details of these reactions can vary depending on the specific acid and other reactants involved.
The slope of a linear velocity-time graph tells us the _____ of the object.
A. Speed
B. Acceleration
The object's acceleration is indicated by the slope of a linear velocity-time graph. Option (B) is the best choice.
A linear velocity-time graph's slope is a representation of an object's acceleration. Acceleration is the rate at which velocity changes in relation to time. When the velocity-time graph is a straight line, a constant acceleration is indicated by the slope of the line.
The acceleration increases with slope steepness and might be positive or negative depending on the slope's direction. If there is no slope (i.e., a horizontal line), there is no acceleration, which means the item is traveling at a constant speed.
As a result, the acceleration is indicated by the slope of the velocity-time graph. (B) is the best choice.
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the ideal mechanical advantage of a pulley system is equal to the
a) distance the load has to move
b) length of the rope
c) number of rope segments supporting the load
d) weight of the object being lifted
Answer: The correct answer is "Number of rope segments supporting the load".
Explanation:
Mechanical advantage: It is defined as the ratio of the force produced by a machine to the force applied on the machine. The ideal mechanical advantage of a machines is mechanical advantage in the absence of friction.
The ideal mechanical advantage of a pulley system is equal to the number of rope segments which is supporting the load. More the rope segments, It is more helpful to do the lifting the work.
It means that less force is needed for this task to complete.
Therefore, the correct option is (C).
1. What are the approximate calorie needs of a
sedentary 16 year old male?
A. 1.800 calories C. 2,200 calories
B 2.000 calories D. 2,400 calories
Answer:
D. 2,400 calories
Which of the following is the method by which air is cooled in the food storage component of a refrigerator?
Question 18 options:
Evaporation
Radiation
Conduction
Convection
Answer: Convection :)
Answer:
D. Convection
Explanation:
The air inside the refrigerator is cooled by convection, which circulates colder air around the food and warmer air out of the refrigerator.
If a spring stores 5 J of energy when it's compressed by 0.5 m, what is the
spring constant of the spring?
O
A. 800 N/m
O
B. 80 N/m
O
c. 40 N/m
O
D. 400 N/m
Answer:
c. 40 N/m
Explanation:
EE = ½ kx²
5 J = ½ k (0.5 m)²
k = 40 N/m
2 Points
Which property will increase if you increase the frequency of an
electromagnetic wave?
O
A. Wavelength
O
B. Shift
O
O
C. Speed
D. Energy
SUBMIT
1. A negatively charged rod is moved near the top of a positively charged electroscope. What
happens to the leaves of the electroscope?
(10 Points)
A)Move closer together
B)Move further apart
C)No change
Answer:
A) Moves closer together
____ occurs when waves spread out and travel around obstacles or through openings in obstacles.
Answer:
diffraction
Explanation:
As you can see from the figure, sound waves spread out and travel around obstacles. This is called diffraction. It also occurs when waves pass through an opening in an obstacle.
What is a scientific law?
A. The best explanation of what science has to offer
B. A description of what happens in nature
C. A testable statement of experimental results
D. A question that can be answered by observation
Answer:
A.
Explanation:
This is the acceleration of an object increases by the force applied to it and decreases based on its mass?
Answer:
who knows bsf
Explanation:
How much current will a 500 W vacuum cleaner draw if it has a resistance of 30Ω?
Answer:
Electric current, I = 4.08 A
Explanation:
We have,
Power of vacuum cleaner is 500 W
Resistance of vacuum cleaner is 30 ohms
It is required to find the current flowing through the vacuum cleaner. It can be calculated using the definition of power delivered. Its formula is given by :
[tex]P=I^2R[/tex]
I is electric current
[tex]I=\sqrt{\dfrac{P}{R}} \\\\I=\sqrt{\dfrac{500}{30}} \\\\I=4.08\ A[/tex]
So, the electric current flowing through the vacuum cleaner is 4.08 A.
4. What is the charge on the leaves of an electroscope if a negatively charged rod is moved near
the top of the electroscope? *
(10 Points)
A)Positive
B)Neutral
C)Negative
Answer:If you bring a negative object near the electroscope, the electrons in the scope will be repelled toward the leaves, balancing the charge. The leaves will move toward each other.
When the negatively-charged rod is brought close to the electroscope, positive charges are attracted to it and negative charges are repelled away from it.
This is called charging by conduction. Figure 2 (c) Charging by Conduction The negatively charged rod touches the knob on the electroscope. The result is a transfer of electrons from the rod to the knob, making the knob, rod, and gold foil all negative, and making the gold foil deflect from the vertical.
Explanation:
A person rubs her hands together and they heat up
• kinetic energy
• light energy
• sound energy
• electrical energy
• chemical energy
• heat energy
(multiple choice)
Answer:
Kinetic and heat energy (heat as thermal)
Explanation:
The friction of the rubbing builds up the energy, so it cant be the types of energy like light or sound
The length of a rope is 5 m. A standing wave on the rope has four nodes. what is the wavelength of the wave
The wavelength of the wave will be 2.5 m.
What is wavelength?The distance between two successive troughs or crests is known as the wavelength. The peak of the wave is the highest point, while the trough is the lowest.
The wavelength is also defined as the distance between two locations in a wave that have the same oscillation phase.
The formula for the length of the rope in relation to the node and wavelength is given by;
[tex]\rm L= \frac{n}{2} \lambda \\\\ \rm 5= \frac{4}{2} \lambda \\\\ \lambda=\frac{5}{2} \\\\ \lambda= 2.5 \ m[/tex]
Hence the wavelength of the wave will be 2.5 m.
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How does the valence of the element relate to its chemical activity ?
The amount of electrons inside an atom's outer shell governs the chemical reactivity and ability to bind with other elements, and this relationship between an element's valence and chemical activity can be seen.
What is valency?In chemistry, an element's valence—also called valency—determines the number of other atoms that an atom of the metal can combine with.
The phrase, which was first used in 1868, is used to indicate both the broad power of a combination of elements and its numerical value. For 19th-century chemists, the explanation and systematization of valence presented significant difficulties.
The majority of the work was on developing empirical rules for finding the connotations of the elements because there was no good hypothesis explaining its source.
For 19th-century chemists, the explanation and systematization of valence posed significant difficulties. The majority of the effort was focused on developing empirical guidelines for finding the electron orbitals of the components because there was no good theory for its cause.
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