The mechanical energy isn't conserved. Some energy is lost to friction.
Option A.
Explanation:The mechanical energy is defined as the energy of a body which it achieves by virtue of its position and velocity. The mechanical energy are of two types - potential energy and kinetic energy. The potential energy is the energy of the body which it achieves by means of its relative position and is directly proportional to the height of the body from its relative plane. Whereas the kinetic energy of the body is achieved by virtue of its velocity and is directly proportional to the square of velocity of the body.
As the mountaineer is skiing down the slope of a mountain, the potential energy of the person is gradually changing into his kinetic energy. Had it been in an ideal situation, the potential energy lost would have been just equal to the kinetic energy gained by the person. But there's friction which opposes the speed of the body and reduces the velocity. Thus the kinetic energy will be lost to some extent and the energy won't be conserved.
the correct answer is B) The mechanical energy isn't conserved. Some energy is lost to friction.
A battery is marked. As having a voltage of 12V and is connected to a circuit that has a resistance of 5 ohms.if the terminal voltage is 8.75V. What is the internal resistance
Answer:
1.857 Ohms
Explanation:
The marked voltage of the battery is it's E.M.F. (Electromotive force). It is the maximum voltage the battery can supply because, ideally internal resistance of a cell or battery should be zero. Let us denote the E.M.F. as E.
In reality we get a lower voltage called the Terminal Voltage (Voltage across the terminals of the battery). Let us call that V. This is due to the voltage drop caused by the internal resistance (say 'r').
So when the circuit is connected a current I flows through a resistance
R(= 5 ohms, given).
Now, potential difference = Terminal Voltage = V = 8.75 Volts
Hence, [tex]I=\frac{V}{R} =\frac{8.75}{5}=1.75 Amperes[/tex]
Now, by conservation of energy we can say that,
E.M.F. = Terminal Voltage + Voltage drop due to the battery's internal resistance
or, [tex]E=V+Ir[/tex]
or, [tex]r=\frac{E-V}{I}=\frac{12-8.75}{1.75}=1.857[/tex] Ohms
Which of the following is true about the movement of stars in the night sky?
A.
Stars in the sky appear to move slowly from south to north.
B.
Stars in the sky appear to move slowly from north to south.
C.
Stars in the sky appear to move slowly from west to east.
D.
Stars in the sky appear to move slowly from east to west.
"Stars in the sky appear to move slowly from east to west" is true about the movement of stars in the night sky.
Answer: Option D
Explanation:
The Sun, Moon and stars all are understood to wake up in the East and set in the West direction, as every 24 hours the Earth rotates on its axis in the reverse direction from West to East. Consequently, the acceleration we witness is not their action, but ourselves as we go zipping onto the Earth's surface to the North, and these gravitational anomalies fly over us. For illustrating this point, the North Star named as Polaris in Ursa Minor is useful.
Stars in the night sky seem to move slowly from east to west due to the Earth's rotation.
Stars in the sky appear to move slowly from east to west. This apparent motion is due to the rotation of the Earth. As the Earth rotates from west to east, the stars appear to move in the opposite direction.
Select the correct answer from each drop-down
Two magnets are placed as shown in the
00
В
D
between the poles B and
. And the force of
between the poles A and DIS
Reset
Next
The force of repulsion between the poles B and C is minimum and the force of attraction between the poles A and D maximum.
Answer: Repulsion, Minimum, Attraction, Maximum
Explanation:
The Concept of attraction & Repulsion
The basic concept of attraction and repulsion between two similar and opposite poles of a bar magnet is that the ends of two bar magnets with similar strongly repel each other whereas poles of opposite polarity attract each other.
Since B and C are of opposite polarity, they will repel each other with minimum forces whereas A and D are of opposite polarity as well, hence they will attract each other with maximum forces when placed together.
We can flip the options accordingly saying, B and C will have the maximum attraction while A and D will have the minimum repulsion when placed together.
Calculate the kinetic energy in joules of a 10 g bullet moving at 300 m/s.
____J
1. 900
2. 450
3. 15
4. 45
Answer:450joules
Explanation:
Let mass=m velocity =v
Mass given=10g=(10/1000)kg=0.01kg
Velocity given =300m/s
Kinetic energy =(m x v^2)/2
Kinetic energy =(0.01x300^2)/2
Kinetic energy =(0.01 x 90000)/2
Kinetic energy =900/2
Kinetic energy =450joules
which description matches with which graph?
Answer:
Description 1 matches C.
Description 2 matches A.
Description 3 matches D.
Description 4 matches B.
Explanation:
Description 1 matches C. From graph C, we can see that the distance remains constant at a particular value. Hence, the car is not traveling and hence it is stopped.
Description 2 matches A. Speed is determined by the gradient of a distance-time graph. A depicts a linear graph which tells us that the gradient is constant and hence the car is at constant speed. The fact that the distance is increasing shows that the car is moving forward.
Description 3 matches D. Graph of D becomes less steeper as time progresses. This tells us that the gradient of the graph is decreasing and hence the speed of the car is decreasing.
Description 4 matches B. Graph B shows distance being decreased. This tells us that the car is coming back.
Write the names of the metalloids in order from lowest to highest atomic number.
Answer:
Boron, silicon, germanium, arsenic, antimony, tellurrin, polonium, Astatine
Explanation:
At which point(s) is the net force the greatest?
At which point(s) is the net force zero?
Final answer:
The net force is the greatest when the forces are in the same direction and have the greatest magnitude. The net force is zero when the forces are balanced and cancel each other out.
Explanation:
The net force on an object is the vector sum of all the forces acting on it. The magnitude of the net force can be determined by considering the individual forces acting on the object. The net force is the greatest at points where the forces acting on the object are in the same direction and have the greatest magnitude.
The net force is zero when the forces acting on the object are balanced and cancel each other out. This occurs at points where the forces are equal in magnitude and opposite in direction.
For example, let's say we have two forces acting on an object: 10 N to the right and 5 N to the left. At the point where the forces are added, the net force would be 5 N to the right (10 N - 5 N). This is the greatest net force. At the point where the forces cancel each other out, the net force would be zero (10 N - 10 N).
which formula is used to calculate the change in an object's momentum
Answer:
The change in momentum of an object is its mass times the change in its velocity.
The formula to calculate the change in momentum of the object is ΔP= m( Vf - Vi).
What is a change in momentum?The change in momentum is equal to the product of the mass and the velocity change. Because mass is a constant value, it remains constant. The change in velocity causes a change in momentum.
The change in momentum is calculated as the difference in the velocities of the object.
Momentum is the product of an object's mass and velocity and describes mass in motion. Impulse: An impulse is a force that causes a change in motion. The change in momentum of an object, p=m(vf-vi) p = m (vf- vI p = m (vf - vI is equivalent to the impulse, J.
Therefore, the formula to calculate the change in momentum of the object is ΔP= m( Vf - Vi).
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Which of the following is the most accurate description of the relationship between velocity
and acceleration?
A. Velocity and acceleration are the same thing.
B. Velocity is a type of acceleration.
C. Acceleration is a change in velocity.
D. Acceleration is positive and velocity is negative.
Answer:
(C) acceleration is a change in velocity.
Explanation :
Acceleration is the rate of change of velocity with time.
Acceleration is the rate at which velocity changes, making option C ('Acceleration is a change in velocity.') the most accurate description of the relationship between velocity and acceleration.
Explanation:The most accurate description of the relationship between velocity and acceleration is that acceleration is the rate at which velocity changes. Therefore, the correct answer to the question is 'C. Acceleration is a change in velocity.'
Acceleration is a vector quantity, which means it has both magnitude and direction. It can result from a change in speed, a change in direction, or both. Velocity is also a vector that describes the speed of an object in a given direction. When an object's velocity changes, it is accelerating, which can be a result of increasing speed, decreasing speed, or changing direction.
In summary, while velocity is the rate of change of position with time, acceleration is the rate of change of velocity with time.
Calculate the work done by a 47 N force pushing a pencil 0.26 m.
Answer:
Workdone = 12.2 Joules
Explanation:
Given:
Force applied on the pencil = 47 N
Displacement of the pencil = 0.26 m
We have to find the work done .
Note:
Workdone = Product of force and its displacement (in the direction of the force) .
So,
Plugging the values.
Workdone = [tex]Force\times displacement[/tex]
⇒ [tex]W=F\times d[/tex]
⇒ [tex]W =47\times 0.26[/tex]
⇒ [tex]W=12.2[/tex] Joules (J)
OR
We can say that the displacement is against the direction of applied force.
Displacement = - 0.26
Workdone = [tex]F\times d\times cos(\theta)[/tex]
⇒ [tex]\theta[/tex] is the angle between force and displacement.
⇒ Here, [tex]\theta=180[/tex]
⇒ [tex]cos(180) = -1[/tex]
Workdone (W) = [tex]Fdcos(\theta)[/tex]
⇒ [tex]47\times -0.26\times -1[/tex]
⇒ [tex]12.2[/tex] Joules (J).
Workdone on pushing the pencil = 12.2 Joules.
Work is the product of the force and displacement. The work done by in the given situation 12.2 J.
Work:
It is the change in the energy due displacement of the object by the applied force. Work is the product of the force and displacement.
W = f.d
Where,
W - work
f- force = 47 N
d - displacement = 0.26 m.
put the values in the formula,
W = 47 N x 0.26 m.
W = 12.2 J
Therefore, the work done by in the given situation 12.2 J.
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The deepest mine ever drilled has a depth of 12300 meters. suppose you drop a rock with a mass of .12 kilograms down the shaft of this mine. What would the rock's kinetic energy be after falling 3200 meters? What would the potential energy associated with the rock be at that same moment? Assume no air resistance and a constant free-fall acceleration. (please show the equations used and why you used these equations.) Thank you.
Answer:
Correct answer: Ek = 384,000 J = 0.384 · 10⁶ J = 0.384 MJ
Ep = 1,092,000 J = 1.092 · 10⁶ J = 1.092 MJ
Et = 1,476,000 J = 1.476 · 10⁶ J = 1.476 MJ
Explanation:
The total energy at all times is equal to the sum of kinetic and potential energy.
Et = Ep + Ek
We will take the bottom of the mine as a reference point
We can solve this problem combined with the help of kinetics and energy conservation laws, or just with energy conservation laws, which I will do.
Before we drop a rock the potential energy is maximum and the kinetic energy is equals to zero.
The formula for calculating potential energy is:
Ep = m g h , we will take that g = 10 m/s²
This is the maximum potential energy (or total energy)
Epmax = Et = 12 · 10 · 12,300 = 1,476,000 J = 1.476 · 10⁶ J = 1.476 MJ
After a fall of 3,200 m the rock will be on height of 9,100 m and its potential energy will be:
Ep = m g h₁ = 12 · 10 · 9,100 = 1,092,000 J = 1.092 · 10⁶ J = 1.092 MJ
The difference between the maximum potential energy (or total energy) and the potential energy at height h₁ is actually kinetic energy.
Ek = ΔEp = Et - Ep = 1,476,000 J - 1,092,000 J
Ek = 384,000 J = 0.384 · 10⁶ J = 0.384 MJ
God is with you!!!
Light in a vacuum travels at a constant speed of 3x10^8 m/s. If the moons average distance from the earth is 38776106 km how long would it take for a beam of light to travel from earth to the moon and back to earth again?
Answer: 258.3 s
Explanation:
The speed [tex]s[/tex] is given by the following equation:
[tex]s=\frac{D}{t}[/tex]
Where:
[tex]s=3(10)^{8} m/s[/tex] is the speed of light in vacuum
[tex]D=2(38776106 km \frac{1000 m}{1 km})=7.75(10)^{10} m[/tex] is the double of the distance between Earth and Moon, since the beam of light travels from Earth to the Moon and back to Earth again.
[tex]t[/tex] is the time it takes to the beam of light to travel the mentioned distance
Isolating [tex]t[/tex] and solving with the given information:
[tex]t=\frac{D}{s}[/tex]
[tex]t=\frac{7.75(10)^{10} m}{3(10)^{8} m/s}[/tex]
Finally:
[tex]t=258.3 s \approx 258 s[/tex]
A 20-newton weight is attached to a spring.
causing it to stretch, as shown in the diagram.
What is the spring constant of this spring?
Answer:
40 N/m
Explanation:
Assuming that the missing diagram is as attached, then we can deduce from Hooke's law that the extension of a spring is directly proportional to the applied force. This is mathematically expressed as
F=kx
Here, F represent the applied force, x denote the extension of the spring while k is the spring constant.
From the attached diagram, extension of the spring x=1-0.5=0.5m
Substituting 20 N for F and 0.5 m for x then
20=0.5k
k=20/0.5=40 N/m
How is temperature and viscosity related?
Answer:
With an increase in temperature, there is typically an increase in the molecular interchange as molecules move faster in higher temperatures. The gas viscosity will increase with temperature. ... With high temperatures, viscosity increases in gases and decreases in liquids, the drag force will do the same.
a 24 volt doorbell carries a current of 1/2 ampere. Calculate the resistance in the bell
1.
2.
3.
Answer:
48Ω
Explanation:
V = I*R
R = Resistance = ?
V = Voltage = 24volt
I = Current = 1/2amp
Therefore,
R = V / I = 24 / (1/2)
R = 24 * 2
R = 48Ω
67. Race Car A race car is slowed with a constant accel-
eration of 11 m/s2 opposite the direction of motion.
a. If the car is going 55 m/s, how many meters will it
travel before it stops?
b. How many meters will it take to stop a car going
twice as fast?
Answer:
a. 137.5 m
b. 550 m
Explanation:
Accelerated Motion
If an object is changing its velocity at a constant rate, it has a uniformly accelerated motion. When the object is moving in one fixed axis, then the sign of the acceleration is negative if the object is braking, and positive if the object is increasing its speed.
The initial speed vo, final speed vt, acceleration a, and distance traveled x are related by the formula
[tex]v_f^2=v_o^2+2ax[/tex]
a. The Race Car A has an initial speed of 55 m/s and it's said to stop. We must find at what distance it goes to vf=0. This means that the above formula becomes
[tex]0=v_o^2+2ax[/tex]
Solving for x
[tex]\displaystyle x=-\frac{v_o^2}{2a}[/tex]
The acceleration is [tex]-11\ m/s^2[/tex], negative because it's against the movement. Thus
[tex]\displaystyle x=-\frac{55^2}{2\times (-11)}[/tex]
[tex]x=137.5\ m[/tex]
b. If the car is going twice as fast (v0=110 m/s), then
[tex]\displaystyle x=-\frac{110^2}{2\times (-11)}[/tex]
[tex]x=550\ m[/tex]
3. What is the net force acting on the box in the diagram below? (1 mark)
Answer: Fnet = 40 N on the right
Explanation: The net force is the summation of forces acting on an object. Add the forces in the same direction and subtract to the opposing force moving in the opposite side.
Fnet= F1 + F2 - F3
= 120 N + 60 N - 140 N
= 180 N - 140 N
= 40 N on the right
Sound travels slower in colder air than it does in warmer air. Make a claim about the effect of air temperature on the speed of sound.
Answer: The temperature of the air affects the speed of sound in the due to the fact that colder contains air molecules with low kinetic energy. For warm air the kinetic energy of the molecules is high causing them to move in rapid motion. Because of these vibrations and collisions sound waves moves in a faster rate.
Explanation:
superposition of a crest and trough produces
Answer:
pure constructive interference
Explanation:
The crests of two waves and the troughs are aligned. The superposition produces pure constructive interference. Because the disturbances add pure constructive interference, it produces a wave that has twice the amplitude of the individual waves but has the same wavelength.
Nitrogen -13 has a half life of 10 minutes how long will it take for a sample of 500 g to be reduced to 62.5 g?
Answer:
30 minutes
Explanation:
Use half life equation:
A = A₀ (½)^(t / T)
where A is the final amount, A₀ is the initial amount, t is time, and T is the half life.
A = A₀ (½)^(t / T)
62.5 = 500 (½)^(t / 10)
0.125 = ½^(t / 10)
t / 10 = 3
t = 30
It will take 30 minutes.
Final answer:
To find the time it takes for a 500 g sample of Nitrogen-13 to be reduced to 62.5 g, we can use the equation for radioactive decay. The time is approximately 40 minutes.
Explanation:
To solve this problem, we can use the equation for radioactive decay: N = N0 * (1/2)(t/t1/2), where N is the final amount, N0 is the initial amount, t is the time passed, and t1/2 is the half-life. In this case, we have N = 62.5 g, N0 = 500 g, and t1/2 = 10 minutes. Substituting these values into the equation:
62.5 g = 500 g * (1/2)(t/10)
Now, we can solve for t by taking the logarithm of both sides and rearranging the equation:
t = 10 * log2(62.5/500)
Using a calculator, the value of t is approximately 40 minutes.
Gizmo weight and mass
Mass refers to the amount of matter in an object. It is a measure of the quantity of particles (atoms and molecules) comprising an object.
Weight, on the other hand, is the force exerted on an object due to gravity.
What is the difference between weight and mass?The terms "weight" and "mass" are often used interchangeably, but they are actually two different things.
Mass is a measure of the amount of matter in an object. It is a scalar quantity, which means that it has magnitude only. Mass is measured in kilograms (kg) or grams (g). The mass of an object does not change, regardless of where it is located or how it is moving.
Weight is a measure of the force exerted on an object due to gravity. It is a vector quantity, which means that it has both magnitude and direction. Weight is measured in newtons (N).
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A short circuit is _____.
Answer:
in a device, an electrical circuit of lower resistance than that of a normal circuit, typically resulting from the unintended contact of components and consequent accidental diversion of the current.
Explanation:
Answer: A short circuit is simply a low resistance connection between the two conductors supplying electrical power to any circuit. This results in excessive current flow in the power source through the 'short,' and may even cause the power source to be destroyed.
Explanation:
Which of the following is not an SI unit?
Answer:
Pound
Explanation:
SI Unit stands for the International Standard of Unit. Thus from the options given, metre is a measure of length which is an SI unit. Kilogram is a measure of mass of a goven matter which is also an SI unit. Second is a measure of time which is an SI unit. Pound is a measure of masswhich is not an SI unit but has to be converted to kilograms which an SI unit.
The pound is not an SI unit, while the kilogram, meter, and nanometer are part of the International System of Units (SI).
The SI (International System of Units) is a globally recognized system of measurement that includes specific base units, derived units, and prefixes for expressing measurements consistently. It was developed to standardize measurements worldwide. Let's identify which of the options is not an SI unit:
Kilogram (kg): The kilogram is one of the seven base SI units and is the unit of mass. It is used to measure the amount of matter in an object. The symbol for the kilogram is "kg."
Meter (m): The meter is another base SI unit and is the unit of length. It is used to measure distance or length. The symbol for the meter is "m."
Nanometer (nm): The nanometer is not a base SI unit, but it is an SI-accepted metric prefix. It represents one billionth (1/1,000,000,000) of a meter (10^-9 meters). It is used for very small lengths, particularly in fields like nanotechnology.
Pound: The pound is not an SI unit. It is a unit of mass commonly used in the United States and a few other countries that have not fully adopted the SI system. The pound is equivalent to approximately 0.453592 kilograms.
So, among the given options, the pound is the unit that is not an SI unit. The other three options (kg, meter, nanometer) are all related to the SI system. The SI system promotes consistency and clarity in scientific measurements and is widely used in most countries around the world.
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The question probable may be:
Which of the following is not an SI unit?
kg , pound, meter, nanometer
An object is located 40.0 cm from a convex lens. The lens focuses light at a
distance of 10.0 cm. What is the image distance?
dof
Use the equation de
The image of distance (di) of the object is 13.33 cm.
Explanation:
Given data in the problem,
The object located at a distance from the convex lens.
do = 40.0 cm
The distance at which the light is focused.
f= 10.0 cm.
We need to find the image of distance di.
The lens equation gives the quantitative relation among the image distance (di), the object distance (do), and the focal length (f).
The equation is given by,
[tex]\frac{1}{f} =\frac{1}{di} +\frac{1}{do}[/tex].
[tex]\frac{1}{10} =\frac{1}{di} +\frac{1}{40}[/tex].
[tex]\frac{1}{10} -\frac{1}{40} =\frac{1}{di}[/tex].
[tex]\frac{4-1}{40}=\frac{1}{di}.\\[/tex]
[tex]\frac{3}{40} = \frac{1}{di}[/tex].
3 di=40.
di=[tex]\frac{40}{3}[/tex].
di = 13.33 cm
The image of distance (di) of the object is 13.33 cm.
A 20-newton weight is attached to a spring.
causing it to stretch, as shown in the diagram.
What is the spring constant of this spring?
Answer:
40 N/m
Explanation:
The diagram attached is used to answer the question
We know from Hooke's law that extension is directly proportional to the applied force hence
F=kx where x is extension, F is applied force and k is the spring constant. Making k the subject of the formula then
[tex]k=\frac {F}{k}[/tex]
From the attached diagram extension is given by subtracting unstretched spring from stretched spring hence extension, x=1-0.5=0.5m
Substituting 20 N for F and 0.5 m for x then
[tex]k=\frac {20}{0.5}=40 N/m[/tex]
A. A boy was at a park one day. The park was _______ (number) meters away from his house.
Based on the graph, I would say the correct answer is 11 meters.
The reason I say this is because if you look at the orange line. He's leaving the park to his home. Is shows that it's 11 meters away. The green line is just there to trick you. It shows that you were already 5 meters closer to the park then at home.
2. A man walks 38 m west from home, rest, then walks 20 m east. What is the man's displacement?
Answer:18m west
Explanation:
Since they are moving in opposite direction we subtract to get the displacement
Displacement =38-20
Displacement =18m in west direction
During a rising tide Ocean waves often become larger if the amplitude of a wave increases by a Factor of 1.1, by how much does the energy increase
Answer:
The energy of the wave will increase by a factor of 1.21.
Explanation:
Given:
The amplitude of the ocean wave is increased by a factor of 1.1.
The energy associated with a wave depends on the amplitude of the wave.
The energy (E) is directly proportional to the square of the amplitude (A) of the wave and is expressed as:
[tex]E=kA^2\\Where\ k\to constant\ of\ proportionality[/tex]
So, if the amplitude is doubled, then the energy will become 4 times and if the amplitude is halved, then the energy reduced by a factor of one by four.
Here, the amplitude is increased by a factor of 1.1. So, the energy associated with it will increase by a factor of square of 1.1 which is given as:
[tex]Increase\ in\ Energy=(1.1)^2=1.21\ of\ the\ initial\ value[/tex]
Therefore, the energy of the wave will increase by a factor of 1.21.
The energy stored in gasoline is
A chemical energy
B electromagnetic energy
C mechanical energy
D nuclear energy
Gasoline stores chemical energy, which can be transformed to other types of energy via chemical reactions, such as the combustion in a car engine.
Explanation:The energy encapsulated within gasoline can be precisely characterized as chemical energy. This type of energy is encapsulated within the chemical bonds of various compounds, encompassing molecules and atoms. It is significant to note that chemical energy, as a versatile energy form, can be both liberated and harnessed as a source of power in diverse applications.
In the case of gasoline, it represents a potent reservoir of chemical energy. When gasoline undergoes combustion in the engine of a car, it engages in a chemical reaction. This reaction leads to the release of the energy contained within the chemical bonds of gasoline molecules. This released energy manifests in the form of mechanical power, propelling the vehicle, and heat energy, which warms the engine and the surrounding environment. In this process, gasoline's chemical energy is converted into mechanical and thermal energy, illustrating the dynamic interplay between different forms of energy in our daily lives.
The precise understanding of chemical energy's role in powering engines and facilitating various industrial processes underscores the fundamental principles of energy transformation and utilization, forming the basis of many technological advancements and applications.
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A 12.0 V battery is attached to a circuit with a resistor of 5.5 Ohms. The internal resistance of the circuit is 1.75 Ohms. What is the terminal voltage of the circuit?
The end voltage is 9.01 volts.
Explanation:The emf of the battery is 12 volts.
The resistance of the circuit = 1.75 ohms.
The resistance of the applicant attached = 5.5 ohms.
So, total resistance of the circuit = [tex]1.75 + 5.5[/tex] ohms = 7.25 ohms.
According to the equation, the voltage applied is equal to the product of the current and the resistance.
V=iR.
So, 12 = [tex]i \times7.25[/tex].
So, i = 1.66.
Therefore, the voltage at the end of the circuit = [tex]12 - 1.66\times1.75[/tex]volts
= 9.01volts.
So the end voltage is 9.01 volts.