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 ...?
A doctor estimates that a particular patient is losing bone density at a rate of 3% annually. The patient currently has a bone density of 1,500 kg/mg3. The doctor writes an exponential function to represent the situation. Which values should the doctor use for a and b in a function written in the form f(x) = abx, where f(x) represents the bone density after x years?
a =
b =
a will be the initial amount so:
a = 1,500 kg/m³
b will be decrease factor so:
1 - 3%
b = 0.97
what is interfacial polarisation ...?
A particular frost-free refrigerator uses about 710kWh of electrical energy per year. Express this amount of energy in J, kJ, & Cal.
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
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
Answer: C.
The gravitational pull of Earth is greater than that of the Moon.
Explanation: plato :3
what must be true of a force that causes an object to move in a circular motion
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 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.
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
What might you have if you dont feel well?
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?
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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When gases, liquids, or solids are in contact with a moving object, the flow of _____ occurs due to frictional forces
When gases, liquids, or solids are in contact with a moving object, the flow of _____ occurs due to frictional forces.
The answer is HEAT
This is becuase when objects flow against friction energy is rubbed with friction causing surfaces to heat from the molecules rubbing.
Why is pluto not a planet?
Pluto is not a planet because it's a dwarf planet it's to small to be a planet.
Hopefully this helped =)!
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
what is the energy of 1 mole of light that has wavelength 400nm? ...?
Calculate the time in which a tuning fork of frequency 256 Kz. completes 32 vibrations?Answer needed urgently. Pl. help. Thanks ! ...?
Which can have either a positive charge or a negative charge when they are released during radioactive decay?
Answer: B on edg
Explanation:
why are the places with high temperature found at the equator ?
Which law describes the magnetic field in a nonlinear 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 ".
Using the scientific definition of work, does a greater amount of force always result in a greater amount of work? Why or why not? ...?
Using the scientific definition of work, a greater amount of force does not always result in a greater amount of work because work done is the result of the force applied and the displacement of that object.
What is the significance of the work done?The work done on an object when the object shows the displacement with respect to the force applied to it and If the force is applied in the same direction as the displacement, work is done on the object, and the work done is equal to the force multiplied by the displacement. The greater force does not show the greater amount of work, as the work done has different factors that it depends upon.
Hence, using the scientific definition of work, a greater amount of force does not always result in a greater amount of work because work done is the result of the force applied and the displacement of that object.
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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.
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)2Given 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.
best for growing most plants, which soil has good drainage and sufficient moisture?
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.
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.
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.
An ionic bond forms between sodium and chlorine when the sodium atoms______ elections
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.Because of friction,
A.energy is not always conserved
B.NOT all potential energy is converted to kinetic energy
C.all of an object's kinetic energy turns into potential energy
D.all of an object's potential energy turns into kinetic energy
According to the big bang theory, the universe was once a very and hostile place.
a.cold
b.restless
c.hot
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
...?
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.
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.
Answer:
The sum of all outputs must equal the input.
Explanation:
What is transferred by electromagnetic waves?
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?
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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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.
Answer:
temperature probe
Explanation:
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.
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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