Which best describes a reference frame?
A. a distance over which an object moves
B. the difference between start and end velocity
C. a position from which something is observed
D. the average speed of a group of objects

Answers

Answer 1
C. a position from which something is Observed.
Answer 2

By definition we have to:

A system or frame of reference are those conventions used by an observer (usually standing at a point on the ground) to be able to measure the position and other physical magnitudes such as speed and acceleration of one or several objects.

The numerical value of some magnitudes can also be relative to the reference system when we refer to the relative movement. There are always mathematical relationships between the observer and the relative magnitudes.

Answer:

C. a position from which something is observed


Related Questions

The purpose of your physics lab is to determine the specific heat of a small metal cylinder. You and your group will use calorimetry, along with a ___________ probe and the law of heat exchange, to calculate specific heat of the metal.

Answers

temperature probe
The difference in temperature is needed for this experiment.

Answer:

temperature probe

Explanation:

what is interfacial polarisation ...?

Answers

Polarization is restriction of the plane of propagation of a wave. Interfacial polarization occurs when a wave crosses from one medium to another where the electric and magnetic properties are different, resulting in the polarization of the wave.

A gas is confined to a cylinder under constant atmospheric pressure, as illustrated in the following figure. When the gas undergoes a particular chemical reaction, it absorbs 829J of heat from its surroundings and has 0.69kJ of P−V work done on it by its surroundings. What is the value of ΔH for this process?

Answers

Final answer:

The value of ΔH for this process is 1.519 kJ.

Explanation:

To calculate the value of ΔH for a process, we need to consider the heat absorbed or released and the work done on or by the system.

In this case, the gas absorbs 829J of heat from its surroundings and has 0.69kJ of P−V work done on it by its surroundings.

The ΔH for this process can be calculated as ΔH = q + w, where q represents the heat absorbed or released and w represents the work done on or by the system. Therefore, ΔH = 0.829 kJ + 0.69 kJ = 1.519 kJ.

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Amy counts the wave crests traveling down a stretched string. Five wave crests pass Amy in two seconds. What is the frequency of the wave?
A. 5.0 Hz
B. 2.5 Hz
C. 10 Hz
D. 2.0 Hz

Answers

the frequency is 5 wave crests / 2 seconds= 5 crests / 2s=2.5c/s
 so it is B. 2.5 Hz 

Which can have either a positive charge or a negative charge when they are released during radioactive decay?

Answers

The correct answer for this question would be the BETA PARTICLES. The one that can have either a positive charge or a negative charge when they are released during radioactive decay are the beta particles. Beta particles are high-energy, high-speed electron or positron emitted in the radioactive decay of an atomic nucleus, in the process of beta decay. Hope this answer helps.

Answer: B on edg

Explanation:

A main sequence star cools and expands. It must be entering which stage?
A. white dwarf
B. black dwarf
C. red giant
D. neutron star ...?

Answers

If a main sequence star is cooling and expanding, it is entering the red giant stage. This means that the star has burned up all of it's hydrogen and is now starting to burn its helium making it cooler.

why are the places with high temperature found at the equator ?

Answers

Places with high temperatures are found at the equator because the equator never is tilted away the from the sun, unlike other parts of the world.
Over the course of a year, the equator is the latitude that receives
the most direct solar rays for the most amount of time.

BUT . . .

The places on Earth where the highest temperatures have been
recorded are NOT on the equator.


When motion IS changing directions, acceleration is the rate at which ________changes, but when motion is NOT changing direction, acceleration may be expressed as the rate at which ________ changes.



A. speed, time
B. velocity, speed
C. elapsed time, average speed


...?

Answers

The best and most correct answer among the choices provided by your question is the second choice or letter B.

When motion IS changing directions, acceleration is the rate at which velocity changes, but when motion is NOT changing direction, acceleration may be expressed as the rate at which speed changes.

I hope my answer has come to your help. Thank you for posting your question here in Brainly. We hope to answer more of your questions and inquiries soon. Have a nice day ahead!

Acceleration is the rate at which velocity changes when direction is involved, and the rate at which speed changes when there is no directional change.

When motion is changing directions, acceleration is the rate at which velocity changes, but when motion is not changing direction, acceleration may be expressed as the rate at which speed changes.

Acceleration is defined as the time rate of change of velocity, which includes both the magnitude and direction of the velocity vector. Therefore, when an object changes its direction, even if maintaining a constant speed, it is still undergoing acceleration because its velocity vector is changing. However, when the direction is constant and only the speed changes, acceleration refers to the rate of this change in speed.

When a 58g tennis ball is served, it accelerates from rest to a constant speed of 36 m/s. The impact with the racket gives the ball a constant acceleration over a distance of 35 cm. What is the magnitude of the net force acting on the ball?

Answers

We first calculate the acceleration on the ball using:
2as = v² - u²; u = 0 because ball is initially at rest
a = (36)²/(2 x  0.35)
a = 1850 m/s²
F = ma
F = 0.058 x 1850
= 107.3 Newtons

Final answer:

The net force exerted on a tennis ball being served, which accelerates from rest to 36 m/s over a distance of 35 cm, is approximately 107.05 N.

Explanation:

To determine the magnitude of the net force acting on a tennis ball being served, we first need to calculate the acceleration of the ball. With an initial speed (vi) of 0 m/s, a final speed (vf) of 36 m/s, and a distance (d) of 0.35 m over which the acceleration occurs, we can use the kinematic equation vf^2 = vi^2 + 2ad to solve for acceleration (a).

vf^2 = 2ad → a = vf^2 / (2d) → a = (36 m/s)^2 / (2*0.35 m) → a ≈ 1845.71 m/s2.

Using this acceleration and the mass of the ball (m), we can then apply Newton's second law, Fnet = ma, to find the net force. The mass of the tennis ball is 0.058 kg (58 g). Thus, Fnet = ma = 0.058 kg * 1845.71 m/s2 → Fnet ≈ 107.05 N.

So, the net force exerted by the racket on the tennis ball is approximately 107.05 N.

A force that holds atoms together is a chemical .

Answers

A force that holds atoms together is a chemical "bond".


Chemical bonds hold atoms together and make brief associations that are fundamental to life. Sorts of chemical bonds including covalent, ionic, and hydrogen bonds and London dispersion forces.  

The chemical bond can be thought of as a power that holds the particles of different components together in such compounds. It opens up the likelihood of a huge number of mixes of the components, and the formation of a large number of new compounds.

Answer:

Therefore, A force that holds atoms together is a chemical bond.

Explanation:

Chemical bond : A chemical bond is a lasting attraction between atoms, ions or molecules that enables the formation of chemical compounds.

Everything in the world around us is made up of atoms, which are tiny pieces of matter. Different atoms stick together to form all kinds of things in the world. A chemical bond is formed when two or more atoms are attracted to each other and form a chemical compound.

Types of chemical bonds including:

Ionic Bonds

Covalent Bonds

The blank is the the distance between two crests or two troughs on a transverse wave. It is also the distance between compressions or the distance between rarefactions on a longitudinal wave.

Answers

"Wavelength" is the distance between two crests or two Troughs.

It is the distance between compressions or the distance between rarefactions on a longitudinal wave too!

So, your final answer is "Wavelength".

Hope this helps!!

Answer : Wavelength.

Explanation :

A disturbance created in a medium produces wave.

In transverse wave, the particles of the medium moves in the direction perpendicular to the direction of propagation of wave.

The uppermost portion of the wave is called the crest and the lower most portion is called the trough.

In longitudinal wave, the particles of medium moves in the same direction of wave i.e. in the direction parallel to the wave.

The particles of medium in longitudinal wave forms compressions and rarefactions. In compression the density of particles in more in a particular space while in rarefaction it is less.

Hence, the wavelength is the the distance between two crests or two troughs on a transverse wave.

It is also the distance between compressions or the distance between rarefactions on a longitudinal wave.

Which electrical protective device is designed to detect a difference in current between circuit wires and interrupt the circuit and stop the flow of electricity?
a. attach ungrounded, two-prong adapter plugs to three-prong cords and tools
b.do not operate electrical equipment when working in wet conditions
c. hold fingers on the switch while carrying a plugged-in tool
d. use gfci only when using double insulated power tools

Answers

That's the description of a ground fault circuit interrupter (GFCI).

The choices you posted seem to belong to a different question.

Temperature measures:
a. the kinetic energy of the random motion of molecules in an object.
b. the kinetic energy of the average motion of molecules in an object.
c. the potential energy of an object.
d. the motion of an object.

Answers

Final answer:

Temperature measures the average kinetic energy of the motion of molecules within an object. This means the faster the average molecular motion, the higher the temperature.

Explanation:

The temperature of an object primarily measures

b. the kinetic energy of the average motion

of molecules in an object. The

kinetic energy

is the energy of motion. Every molecule in an object is in motion and hence possesses some kinetic energy. This motion could be translational (moving from one place to another), vibrational (moving back and forth), or rotational (spinning). The more kinetic energy they have, the faster they are moving, and the higher the temperature of the object. It's important to note that we are talking about the

average

kinetic energy per molecule, and not the total kinetic energy of all the molecules, as different molecules might be moving at different speeds.

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A particular frost-free refrigerator uses about 710kWh of electrical energy per year. Express this amount of energy in J, kJ, & Cal.

Answers

Final answer:

To convert the energy usage of a refrigerator from kWh to J, kJ, and Cal, we multiply by appropriate conversion factors. The refrigerator uses 2.556 × 10^9 J, 2.556 × 10^6 kJ, and approximately 610,868 Cal per year. At an electricity cost of $0.15 per kWh, it costs $106.50 per year to run.

Explanation:

To answer the question on how to convert the annual energy usage of a frost-free refrigerator from kilowatt-hours (kWh) to Joules (J), kilojoules (kJ), and Calories (Cal), we can use the following conversion factors:

1 kWh = 3.6 × 10^6 J (Joules)

1 J = 0.001 kJ (kilojoules)

1 Cal = 4.184 kJ (the food Calorie, with a capital 'C', is equivalent to a kilocalorie)

Now, we will convert the 710 kWh/year:

To Joules: 710 kWh × 3.6 × 10^6 J/kWh = 2.556 × 10^9 J

To kilojoules: 2.556 × 10^9 J × 1 kJ/1000 J = 2.556 × 10^6 kJ

To Calories: Using the relationship between kJ and Cal: 2.556 × 10^6 kJ / (4.184 kJ/Cal) ≈ 610,868 Cal

The cost to run such a refrigerator at a typical electricity cost of $0.15 per kWh can be calculated as follows:

Annual Cost = 710 kWh/year × $0.15/kWh = $106.50/year

When a car screeches to a sudden stop to avoid hitting a dog, it slows down from 9.00 m/s to 0.00 m/s in 1.50 s. Find the average acceleration of the car.

Answers

The formula for acceleration is
[tex]a=\frac{\Delta v}{t}[/tex]
where [tex]a=[/tex] acceleration, [tex]\Delta v=[/tex] change in velocity, and [tex]t=[/tex] time

So we get
[tex]a=\frac{-9.00\ m/s}{1.50\ s}[/tex]
[tex]\rightarrow a=-6.00\ m/s^{2}[/tex]

Answer:

a = - 6 m/s/s

here negative sign shows that velocity is decreasing with time

Explanation:

As we know that average acceleration is given by

[tex]a_{avg} = \frac{v_f - v_i}{\Delta t}[/tex]

here we will have

[tex]v_f[/tex] = final speed = 0 m/s

[tex]v_i[/tex] = initial speed = 9 m/s

[tex]\Delta t[/tex] = time interval = 1.50 s

now from above equation we will have

[tex]a = \frac{0 - 9}{1.5}[/tex]

[tex]a = - 6 m/s^2[/tex]

so average acceleration will be -6 m/s/s

Which law describes the magnetic field in a nonlinear wire?

Answers

Lenz's law describes the magnetic field of non linear wire

Answer:

Lenz's law

Explanation:

Lenz's Law states that the induced tensions will be such that they oppose the variation of the magnetic flux that produced them; However, this law is a consequence of the principle of conservation of energy.

Lenz's Law: "The sense of the currents or induced electromotive force is such that it always opposes the cause that produces it, that is, the variation of the flow."

Thanks to the already named Lenz Law, the Faraday Law was completed, so it is common to also call it the Faraday-Lenz Law to honor its efforts in the problem, Russian physicists always use the name "Faraday-Lenz Law ".

what must be true of a force that causes an object to move in a circular motion

Answers

It acts perpendicular to the velocity and is directed
toward the center of the circle.

Answer:

The correct answer is: It acts perpendicular to the velocity and is directed toward the center of the circle.

Explanation:

The Centripetal Force is when an object that describes a circular path has the feeling that it is carried inside the center of the circumference described. This indicates that the centripetal force acts with attraction on the body, indicating the directions that it must take.

In other words, the centripetal force is the force that acts on a moving object on a curvilinear path, and that is directed towards the center of path curvature.

When the object moves in a curvilinear direction, the centripetal force will always act perpendicular to the known direction, that is, it always acts perpendicular to the direction of movement of the body on which it is applied.

Given all this, it is possible to say that the correct answer is: It acts perpendicular to the velocity and is directed toward the center of the circle.

When a substance undergoes a phase change it still has a definite....

Answers

It still has a definite temperature.

If a resistor of R ohms is connected across a battery of E colts with internal resistance r ohms, then the power (in watts) in the external resistor is \[P = \frac{E^2R}{(R+r)^2}\]
If E and r are fixed but R varies, what is the maximum value of the power?

Answers

Final answer:

The maximum power in the external resistor R, when connected to a battery of E volts and internal resistance r, occurs when R equals r. This is a principle of electrical power in physics.

Explanation:

This is a physics question involving a fundamental concept in electrical power and Ohm's Law. The given formula P = E^2R/(R+r)^2 is the power delivered to an external resistor R when it is connected to a battery with electromotive force (E) and internal resistance (r).

To find the maximum power in the external resistor R, we would differentiate the formula with respect to R and equal it to zero (since the maximum or minimum of a function translates to a derivative of zero). By doing this, R would be equal to r.

Therefore, the maximum power is distributed to the external resistor when the value of the resistor (R) equals the internal resistance (r).

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According to the big bang theory, the universe was once a very and hostile place.

a.cold
b.restless
c.hot

Answers

According to the big bang theory, the universe was once a very C. hot and hostile place, and it expanded rapidly. This rapid expansion was the very reason it eventually cooled down and eventually got to its present state where all the planets and galaxies and what not were created. 

What is transferred by electromagnetic waves?

Answers

Energy (electromagnetic radiation) is transferred through vibrations of electric and magnetic fields.

. How much work in joules is done by a person who uses a force of 25 N to move a desk 3.0 m?

Answers

We Know, W = F * s
here, F = 25 N
s = 3 m

Substitute it into the expression,
W = 25 * 3
W = 75 Joule

So, your final answer is 75 J

Hope this helps!

Final answer:

The work done by a person using a force of 25 N to move a desk 3.0 m is 75 Joules, calculated by multiplying the force and the distance.

Explanation:

The concept in question is related to work and energy, under Physics. The work done by a force is defined as the product of the force and the distance over which the force acts, given by the formula: Work = Force x Distance. This implies that the work done is equal to the value of the force (in newtons) multiplied by the distance (in meters) over which the force is applied. In this case, a force of 25 N is acting to move a desk over a distance of 3 m. The work done can be calculated by multiplying the force and the distance: 25 N x 3 m = 75 J (Joules).

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The universe is mostly made up of what?
a. interstellar matter
b. particles of dust and gas
c. stars
d. empty space

Answers

D. Empty Space

Imagine an apple in the center of a football field. Pretend like that apple is the nucleus of an atom. The electrons would be at the end-zones. The universe is just a butttonne of empty space

What might you have if you dont feel well?

Answers

you may have a cold if you do not feel well, depends on the symptoms
you will have medicine

Two basketball players are essentially equal in all respects. (They are the same height, they jump with the same initial velocity, etc.) In particular, by jumping they can raise their centers of mass the same vertical distance, (called H their "vertical leap"). The first player, Arabella, wishes to shoot over the second player, Boris, and for this she needs to be as high above Boris as possible. Arabella jumps at time , and Boris jumps later, at time (his reaction time). Assume that Arabella has not yet reached her maximum height when Boris jumps.


1)Find the vertical displacement , D(t) = H(a)(t) - H(b)(t) as a function of time for the interval 0 < t < t(r) , where H(a)(t) is the height of the raised hands of Arabella, while H(b)(t) is the height of the raised hands of Boris.

Express the vertical displacement in terms of H, g , and t.

Answers

Final answer:

The vertical displacement D(t) between two jumping basketball players can be found using the kinematic equation for vertical motion. By accounting for the later jump time of the second player, we can subtract their height functions to find the displacement as a function of time in terms of initial height H, gravitational acceleration g, and time t.

Explanation:

The student's question involves calculating the vertical displacement of two basketball players, Arabella and Boris, during their jumps, with Arabella starting her jump before Boris. To find the vertical displacement D(t) as a function of time, we need to consider the kinematic equation for vertical motion H(t) = V0t - (1/2)gt2, where V0 is the initial vertical velocity, g is the acceleration due to gravity (9.8 m/s2), and t is the time.

Assuming both players have the same V0 and are affected by the same g, the displacement of each player at any time t is given by:

For Arabella: H(a)(t) = V0t - (1/2)gt2For Boris: H(b)(t) = V0(t - tr) - (1/2)g(t - tr)2

Given that Boris starts jumping at time tr later than Arabella, his height function H(b) has t - tr. The vertical displacement D(t) between Arabella and Boris from 0 < t < tr can be found by subtracting the height of Boris from the height of Arabella:

D(t) = H(a)(t) - H(b)(t)

Substituting in the expressions for H(a)(t) and H(b)(t) gives us the final expression for D(t) in terms of the known quantities H, g, and t.

What is the basis for analyzing an energy transfer diagram? The mechanical energy input and output must be equal.  Heat must always be the largest output. The sum of all outputs must equal the input.  Electrical energy is an input but not an output.

Answers

An Energy Transfer Diagram is also known as Sankey diagram and this shows the input energy taken in and the transformation of the output energy in another form. Therefore the basis for analyzing an energy transfer diagram would be the sum of all outputs must equal the input. Therefore, it is the third option. Hope this answer helps.

Answer:

The sum of all outputs must equal the input.

Explanation:

Which of the following conversion factors would you use to change 18 kilometers to meters?
A.) 1,000 m/1 km
B.) 1 km/1,000 m
C.) 100 m/1 km
D.) 1 km/100 m

Answers

use choice B. 1 km / 1000 m 

from what result that 18 km = 18 000 m 

hope helped 

Answer:

The answer is A) 1,000 meters = 1 Kilometer.                                                        

Explanation:

To convert 18 Kilometers into meters, one would have to  multiply the figure given in Kilometer by 1000.

Therefore we have 18 x 1000

= 18,000.

So 18 Kilometers is also 18,000 meters when converted.

Cheers!

Why is the weight of an object more on earth than on the mood ?
A.the mood is a satellite of earth
B. The gravitational pull of the mood is greater than of earth
C. The gravitational pull of earth is greater than that of the moon
D. The objects mass is different on earth and on the moon

Answers

1. moon* lol
And your answer is C. If objects weigh more one one planet than the other, that planet has stronger gravitational pull.

Answer: C.

The gravitational pull of Earth is greater than that of the Moon.

Explanation: plato :3

An ionic bond forms between sodium and chlorine when the sodium atoms______ elections

Answers

The answer is donate
Answer;

Donate

An ionic bond forms between sodium and chlorine when the sodium atoms donate elections

Explanation;Ionic bond is a type of bonds that results from transfers of electrons from one atom to another.  This types of bond is formed between metals and non metals.Metals lose electrons to form cations (positively charged ion) and non metals gain electrons forming anions, negatively charged ion. In this case, sodium donates and electron to chlorine atom, thus they both achieve a stable electronic configuration forming ions.

best for growing most plants, which soil has good drainage and sufficient moisture?

Answers

The correct answer is "loam".

Answer:

Sandy Loam soil

Explanation:

The ideal properties of a soil for growing plants is to have a reasonable drainage, good amount of aeration,  pH value of the soil that allows the availability of all the elements such as potassium, iron, calcium, magnesium, nitrogen etc for growth. Loam soil has the features mentioned above and hence it makes a good choice.

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what ions would you expect to find when an acid dissolves in water? Timothy, a cashier, is given a twenty-dollar bill at his store. He is suspicious of the customer and wants to make sure the currency is real. Which would be a clue that the currency is counterfeit? There are watermarks in the paper bill. There is a security thread in the paper bill. There is no gold standard backing the bill. There is no change in the color of the bill's ink. contemporary and modern a. synonyms b. antonyms c. neither In a bag, a child has 325 coins worth $19.50. There were three types of coins: pennies, nickels, and dimes. If the bagcontained the same number of nickels as dimes, how many of each type of coin was in the bag? If gas in a sealed container has a pressure of 50 kPa at 300 K, what will the pressure be if the temperature rises to 360 K? besides hydrogen and oxygen what is required to produce the chemical reaction that yields water 1. What type of power does the Constitution grant to the Supreme Court? (1 point)executive power federal power judicial power legislative power 2. Which are examples of judicial restraint in the Supreme Court? Select all that apply. (3 points)The verdict overturns the lower courts ruling and sets a new precedent.The verdict is narrowly for the defendant, letting the previous verdict stand.The court uses previous cases as examples of what path to follow in their verdict.The court decides that the law must be rewritten to provide civil liberties for all.The court refuses to hear a case. The persian ruler Cyrus was called "the Great" because he?a. Showed no mercy to enemiesb. Thought Persian culture was superior to othersc. Was a large mand. Showed wisdom and compassion please give me answers A verb that is combined with the main verb to tell about an action A. Transitive Verb B. Intransitive Verb C. Linking verb. D. Helping Verb Whats 8 yards : 40 feet in silliest form felicidada.sadnessb.madnessc.happiness Select all ratios equivalent to 21:14.14:10, 8:4, 9:6, 12:21 The students were bored. They didn't know this history would be important to them. correct?? Locate the participle phrase and the word it modifies.The picture drawn by Melissa is clever. Read this line from the poem. The untamed heart to hand I broughtWhat is the meaning of the figurative language in this line?A.)The speaker is a true romantic.B.)The speaker likes relationships with untamed people.C.)The speaker has overcome the resistance of a partner who has never loved before.D.)The speaker is saying that the person is wild and undisciplined. If the gene for a trait is carried on an x or y chromosome, it's a _______ trait. dominant sexlinked codominant polygenic Davie and Horatio are riding their motorbikes on a scenic tour that is 80 miles long. Davie rides at 20 miles per hour and leaves 90 minutes before Horatio. How fast must Horatio ride to finish at the same time as Davie? The box plots show student grades on the most recent exam compared to overall grades in the class.Which of the following best describes the information about the medians?A. The class and exam medians are almost the same.B. The exam median is much higher than the class median.C. The class and exam Qv3 are the same, but the exam has the lowest median.D. The low outlier on exams pulls the median lower. Why would the people not support public education in the early years of the country?Public education would require large amounts of tax dollars.Education was only needed for the wealthy who were not laborers.Private schools had done the job well in the past.Poor people had no need of an education.