Answer:
Maybe A is the correct answer
A spherical cell has a radius of 2.3 μm , and the phospholipid bilayer that constitutes its membrane has a thickness of 3.75 nm . At its normal resting state, the outer membrane is at a voltage of 0V, and the inner membrane is at a voltage of -70mV. The dielectric constant of the cell membrane is roughly 9.0. What is the capacitance of the cell? (Note: the surface area of a sphere is 4πr2)
Answer:
Explanation:
The cell is acting like a shell .
Capacity of a shell is given by the following expression.
C= 4πk ε₀ x ab / (b-a )
k is dielectric constant , b and a are outer and inner radius ε₀ is a constant .
Here a = 2.3 x 10⁻⁶ m
b = 2.3 x 10⁻⁶ + .00375 x 10⁻⁶
= 2.30375 x 10⁻⁶ m
b -a = 3.75 x 10⁻⁹ m .
k = 9
4π ε₀ = 1 / 9 x 10⁹ = .111 x 10⁻⁹
C= .111 x 10⁻⁹ x 9 x 2.3 x 10⁻⁶ x 2.30375 x 10⁻⁶ / 3.75 x 10⁻⁹
= 1.41 x 10⁻¹² F
= 1.41 pF .
what is the efficiency of an engine that dies 288 J of work and exhausts 72 J of heat while taking 360 J of heat?
Answer:
80%
Explanation:
Energy Input: 360 J
Energy Output: 288 J
e= 288/360 × 100
e= 80%
Alternatively,
e= W(total)/ Q (in)
e= 288/360
e=0.8×100
e=80%
A completely inelastic collision occurs between two balls of wet putty that move directly toward each other along a vertical axis. Just before the collision, one ball, of mass 3.0 kg, is moving upward at 22 m/s and the other ball, of mass 1.3 kg, is moving downward at 11 m/s. How high do the combined two balls of putty rise above the collision point
Answer:
The height balls rise above the collision point, is approximately 7.37 meters
Explanation:
The given parameters just before the collision are;
The mass, m₁ and velocity, v₁ of the ball moving upward are;
m₁ = 3.0 kg, v₁ = 22 m/s
The mass, m₂ and velocity, v₂ of the ball moving downward are;
m₂ = 1.3 kg, v₂ = -11 m/s (downward motion)
The type of collision = Inelastic collision
We note that the momentum is conserved for inelastic collision
Let, [tex]v_f[/tex], represent the final velocity of the balls after collision, we have;
∴ Total initial momentum = Total final momentum
m₁·v₁ + m₂·v₂ = (m₁ + m₂)·[tex]v_f[/tex]
Therefore, we get;
m₁·v₁ + m₂·v₂ = 3.0 kg × 22 m/s + 1.3 kg × (-11) m/s = 51.7 kg·m/s
(m₁ + m₂)·[tex]v_f[/tex] = (3.0 kg + 1.3 kg) ×
∴ 51.7 kg·m/s = 4.3 kg × [tex]v_f[/tex]
[tex]v_f[/tex] = (51.7 kg·m/s)/4.3 kg ≈ 12.023 m/s
The final velocity, [tex]v_f[/tex] ≈ 12.023 m/s
The maximum height, h, the combined balls will rise from the point of collision, moving upward at a velocity of [tex]v_f[/tex] ≈ 12.023 m/s, is given from the kinetic equation of motion, v² = u² - 2·g·h, as found follows
At maximum height, we have;
[tex]h_{max} = \dfrac{v_f^2}{2 \cdot g }[/tex]
Therefore;
[tex]h_{max} \approx \dfrac{12.023^2}{2 \times 9.81 } \approx 7.37[/tex]
The height the combined two balls of putty rise above the collision point, [tex]h_{max}[/tex] ≈ 7.37 m.
definition of matter . A object which cover the place and have mass is called matter
Answer:
you have written the definition so what are you asking
Two objects, one with a mass of and the other with a force of 30.0kg experience a gravitational force of attraction of 7.50 * 10^- 8 N how far apart are centers of mass?
Answer:
Explanation:
The formula for this is
[tex]F_g=\frac{Gm_1m_2}{r^2}[/tex] where F is the gravitational force, G is the gravitational constant, m1 is the mass of one object and m2 is the mass of the other object. We are looking for r, the distance between the centers of their masses.
Filling in:
[tex]7.5*10^{-8}=\frac{6.67*10^{-11}(90.0)(30.0)}{r^2}[/tex] and moving things around to solve for r:
[tex]r=\sqrt{\frac{6.67*10^{-11}(90.0)(30.0)}{7.5*10^{-8}} }[/tex] Doing all that and rounding to the 3 sig fig's you need gives us a distance of 1.55 m
Principles What are the advantages of total reflecting prism over plane mirror?
Answer:
There is no significant energy loss in the total internal reflection and the reflected ray has entire light wave energy so that a brighter image is formed, but some energy in the plane mirror is absorbed inside and thus energy loss.
Explanation:
Advantages
If the light is reflected from the total prism, the entire light is completely reflected internally. But only about 90% of the incident light is reflected from the mirror of the plane. Consequently, reflected light intensity is more in the prism than light reflected in the plane mirror. There are no more reflections in the prism as in the plane mirror in its entirety. In the case of a total prism as in the plane mirror, the image is not reversed laterally. It requires no silvering, one of the benefits.Q011) The Doppler effect a. occurs when the frequency of sound waves received is lower if the wave source is moving toward you than if it's moving away. b. occurs when the pitch of a sound gets lower if the source is receding. c. is the basic explanation for the blue shift of light in our Universe. d. can be applied only to sound waves.
Answer:
Option (c) is correct.
Explanation:
The apparent change in the frequency of light due to the relative motion between the source and the observer is called Doppler's effect.
When the source is moving towards the observer which is at rest, the apparent frequency increases and if the observer is moving away the frequency of sound decreases.
It occurs for both light and sound.
So, to explain the blue shift of light in the universe is due to the Doppler's effect of light.
A car travelling at 10ms ,acceleration uniformly at 2ms what will be its velocity after 5s?
[tex]we \: know \: that \\ acceleration = \frac{(final \: velocity - initial \: velocity)}{time} \\ = > a = \frac{(v - u)}{t} \\ = > 2m {s}^{ - 2} = \frac{{(v - 10m {s}^{ - 1} })}{5s} \\ = > 2m {s}^{ - 2} \times 5s = v - 10m {s}^{ - 1} \\ = > 10m {s}^{ - 1} = v - 10m {s}^{ - 1} \\ = > 10m {s}^{ - 1} + 10m {s}^{ - 1} = v \\ = > 20m {s}^{ - 1} = v \\ = > 20m {s}^{ - 1} = initial \: velocity[/tex]
Hope it helps!!
Thanks!!
Answer:
20 ms
Explanation:
You know
acceleration=2ms initial Velocity=10ms Time=5s
We are finding Final V
Use the equation Final v = (a x t) + initial v
2 x 5 = 10
10 + 10 = 20
what is physical change ?
Answer:
Physical Changes :- The substance in which no new substance is formed are called physical changes.
The molecular composition of the substance are totally same.
For example :- Crushing a mineral into powder.
Juanita ran one mile around her school track in six minutes. What is
her average speed, and what is the magnitude of her average velocity?
10 mph, 0 mph
6 mph, 0 mph
6 mph, 6 mph
10 mph, 10 mph
Answer:
The correct option is a) 10 mph, 0 mph.
Explanation:
1. The average speed (S) is a magnitude given by:
[tex] S = \frac{D}{T} [/tex]
Where:
D: is the total distance = 1 mi
T: is the total time = 6 min
[tex] S = \frac{D}{T} = \frac{1 mi}{6 min}*\frac{60 min}{1 h} = 10 mph [/tex]
Hence, the average speed is 10 mph.
2. The average velocity is a vector:
[tex] V = \frac{\Delta d}{\Delta t} = \frac{d_{f} - d_{i}}{t_{f} - t_{i}} [/tex]
Where:
[tex]d_{f}[/tex]: is the final distance
[tex]d_{i}[/tex]: is the initial distance
[tex]t_{f}[/tex]: is the final time
[tex]t_{i}[/tex]: is the initial time
Since Juanita ran one mile around her school track, the final position is the same that the initial position, so the magnitude of the average velocity is zero.
Therefore, the correct option is a) 10 mph, 0 mph.
I hope it helps you!
How does sound travel?
a wave in which particles of the medium vibrate at right angles to the direction that the wave travels is called?
Explanation:
Longitudinal waves are waves in which the vibration of the medium is parallel to the direction the wave travels and displacement of the medium is in the same (or opposite) direction of the wave propagation. Mechanical longitudinal waves are also called compressional or compression waves, because they produce compression and rarefaction when traveling through a medium, and pressure waves, because they produce increases and decreases in pressure.
Answer:
In transverse waves, particles of the medium vibrate to and from in a direction perpendicular to the direction of energy transport.
Explanation:
hope it will help u
convert the following as instructed
67 kg into gram
explain step by step
please reply quickly its urgent
Answer:
1kg = 1000g
67kg therefore would be equal to
67 x 1000 = 67,000g = 6.7 x 10⁴g.
The difference between starting and ending
positions is
distance
displacement
Answer:
displacement
Explanation:
Motion can be defined as a change in the location (position) of a physical object or body with respect to a reference point.
This ultimately implies that, motion would occur as a result of a change in location (position) of an object with respect to a reference point or frame of reference i.e where it was standing before the effect of an external force.
A reference point refers to a location or physical object from which the motion (movement) of another physical object or body can be determined.
Mathematically, the motion of an object is described in terms of acceleration, time, distance, speed, velocity, position, displacement, etc.
Displacement can be defined as the change in the position of a body or an object. It is a vector quantity because it has both magnitude and direction.
This ultimately implies that, the difference between the starting and ending positions of a physical object is generally referred to as displacement
A scientist that applies the laws of science to the needs of communities is called _____.
the experimental scientist
the engineer
the teacher
the technician
Answer:
The experimental scientist
Which of the following is defined as a force that pushes and pulls the current through the circuit? Group of answer choices D) resistance B) electricity A) current C) voltage
Answer:
C voltage
Explanation:
Voltage is the change in electric potential so basically current flows from high potential to low potential due to voltage.
A flywheel turns through 40 rev as it slows from an angular speed of 1.5 rad/s to a stop. (a) Assuming a constant angular acceleration, find the time for it to come to rest. (b) What is its angular acceleration
Answer:
The time of motion is 333.3 s
The angular acceleration is -0.0045 rad/s²
Explanation:
Given;
angular distance of the flywheel, θ = 40 rev
initial angular speed, [tex]\omega_i[/tex] = 1.5 rad/s
When the wheel comes to rest, the final angular speed, [tex]\omega_f[/tex] = 0
The angular acceleration is calculated as follows;
[tex]\omega_f^2 = \omega_i^2 + 2\alpha \theta \\\\0 = (1.5 \ rad/s)^2 + 2\alpha (40 \ rev\times \frac{2\pi \ rad}{1 \ rev} )\\\\0 = 2.25 + 160\pi \alpha\\\\160\pi \alpha = - 2.25\\\\\alpha = -\frac{2.25 }{160\pi} \\\\\alpha = -0.0045 \ rad/s^2[/tex]
The time of motion is calculated as;
[tex]\omega_f = \omega _i + \alpha t\\\\0 = 1.5 + (-0.0045t)\\\\0 = 1.5 - 0.0045t\\\\0.0045t = 1.5\\\\t = \frac{1.5}{0.0045} = 333.3 \ s[/tex]
Atoms can create fields to interact with each other without touching.
True
or
False
Answer:
True
Explanation:
True, atoms create electromagnetic fields that form repulsion to keep them from touching.
sam says that beta particles are not used to irradiate food because they make it radioactive. Jo says that the reason is that beta particles would not be able to penetrate all the way through think packages of food. Who is correct, Sam or Jo?
Answer:
Jo
Explanation:
irradiating food doesn't make it radioactive (that's contamination) and beta particles are stopped by aluminium foil or thin metals, so it may not pass through thick packaging (usually gamma is used to irradiate foods as it can pass through the packaging)
in parallel combination of electrical appliances Total Electric Power a. increase b. decrease c. remain same
Answer:
In a parallel combination of electrical appliances total electric power will increase
Answer is A it will increase
A distant planet with a mass of (7.2000x10^26) has a moon with a mass of (5.0000x10^23). The distance between the planet and the moon is (6.10x10^11). What is the gravitational force between the two objects?
A distant planet with a mass of (7.2000x10^26) has a moon with a mass of (5.0000x10^23). The distance between the planet and the moon is (6.10x10^11). What is the gravitational force between the two objects?
Answer:
Explanation:
This is a simple gravitational force problem using the equation:
[tex]F_g=\frac{Gm_1m_2}{r^2}[/tex] where F is the gravitational force, G is the universal gravitational constant, the m's are the masses of the2 objects, and r is the distance between the centers of the masses. I am going to state G to 3 sig fig's so that is the number of sig fig's we will have in our answer. If we are solving for the gravitational force, we can fill in everything else where it goes. Keep in mind that I am NOT rounding until the very end, even when I show some simplification before the final answer.
Filling in:
[tex]F_g=\frac{(6.67*19^{-11})(7.2000*10^{26})(5.0000*10^{23})}{(6.10*10^{11})^2}[/tex] I'm going to do the math on the top and then on the bottom and divide at the end.
[tex]F_g=\frac{2.4012*10^{40}}{3.721*10^{23}}[/tex] and now when I divide I will express my answer to the correct number of sig dig's:
[tex]Fg=[/tex] 6.45 × 10¹⁶ N
Un móvil recorre una trayectoria en línea recta de 6000 metros y demora 30 minutos. ¿Cuál es su rapidez expresada en Km/h?
Answer:
La rapidez del móvil es 12 kilómetros por hora.
Explanation:
Asumamos que el móvil experimenta un movimiento rectilíneo uniforme, cuya ecuación cinemática es la siguiente:
[tex]v = \frac{x}{t}[/tex] (1)
Where:
[tex]x[/tex] - Distancia recorrida, en kilómetros.
[tex]t[/tex] - Tiempo, en horas.
[tex]v[/tex] - Rapidez, en kilómetros por hora.
Si tenemos que [tex]x = 6000\,m[/tex] y [tex]t = 30\,min[/tex], entonces la rapidez del móvil es:
[tex]v = \frac{6000\,m\times \frac{1}{1000}\,\frac{km}{m}}{30\,min \times \frac{1}{60}\,\frac{h}{min} }[/tex]
[tex]v = 12\,\frac{km}{h}[/tex]
La rapidez del móvil es 12 kilómetros por hora.
a trampoline launches a 50kg person 2m into the air. if the springs push with 1960N of force, how much displacement was there in the trampoline
Answer: 0.5 m
Explanation:
Given
Mass of the person is [tex]m=50\ kg[/tex]
Trampoline launches the person into the air up to height of [tex]h=2\ m[/tex]
Force experience by springs is [tex]F=1960\ N[/tex]
Here, the work done on displacing the springs is equivalent to the Potential energy acquired by the person i.e.
[tex]\Rightarrow F\cdot x=mgh\quad [\text{x=displacement of the trampoline}]\\\\\text{Insert the values}\\\\\Rightarrow x=\dfrac{50\times 9.8\times 2}{1960}\\\\\Rightarrow x=\dfrac{980}{1960}\\\\\Rightarrow x=0.5\ m[/tex]
Answer:
0.5
Explanation:
Se lanza una pelota de béisbol desde la azotea de un edificio de 25 m de altura con velocidad inicial de magnitud 10 m/s y dirigida con un ángulo de 63.1° sobre la horizontal. A) ¿Qué rapidez tiene la pelota justo antes de tocar el suelo? Use métodos de energía y desprecie la resistencia del aire.
Answer:
v_f = 24.3 m / s
Explanation:
A) In this exercise there is no friction so energy is conserved.
Starting point. On the roof of the building
Em₀ = K + U = ½ m v₀² + m g y₀
Final point. On the floor
Em_f = K = ½ m v_f²
Emo = Em_g
½ m v₀² + m g y₀ = ½ m v_f²
v_f² = v₀² + 2 g y₀
let's calculate
v_f = √(10² + 2 9.8 25)
v_f = 24.3 m / s
(Serious Please) patulong
Answer:
a. Potential energy is highest at Part A
The kinetic energy is highest at Part C and Part D
b. The potential energy is lowest at Part C and Part D
c. The roller coater has equal amount of potential and kinetic energy at Part B, Part D and part F
2) Yes, the mechanical energy is the same from point A to F according to the first law of thermodynamics
Explanation:
The total mechanical energy is constant where the roller coaster moves by only the initial velocity, and the the force of gravity
Total mechanical energy, M.E. = Kinetic energy, K.E. + Potential energy, P.E.
M.E. = K.E. + P.E. = Constant
Therefore, we have;
a. Potential energy is the energy stored in a body, due to its position or elevation, state or arrangement
The higher the elevation, the higher the potential energy, therefore, the highest amount of potential energy is gained when the roller coaster is at the highest point in the motion = Part A
From M.E. = K.E. + P.E. = Constant, the highest kinetic energy is given at the point the roller coaster has the lowest potential energy, which corresponds with the lowest points = Part C and Part D
b. Potential energy, which is the energy of body due to its position or state is lowest at the lowest points = Part C and Part D
c. The value of potential energy, P.E. due to elevation, can be found as follows
P.E. = Mas, m × Gravity, g × Height, h
Therefore, the potential energy will be half the maximum value where the height, h = (Maximum height)/2 and given that M.E. = K.E. + P.E., the kinetic energy, will increase by the same amount, and we have;
K.E. = P.E. at the half the maximum height of the track = Part B, Part D and part F
2) The mechanical energy is the input energy, which according to the first law of thermodynamics cannot be created and destroyed an it is therefore, constant and it is the same from point A to F
the unit of energy is same as that of work i.e joule give reason
"Energy" is the ability to do work.
"Work" is the process of using energy.
A delivery boy on a bicycle drags a wagon full of newspapers by pedaling at 0.90 m/s for 45 minutes using a force of 40 N. How much work has the boy done?
Answer:
Explanation:
The equation for work is
W = FΔx
We are looking for work, so that means we have to be able to fill in the Force and the displacement. We have Force, but we don't have displacement. But the thing we need to do first is change the 45 minutes to seconds because the velocity is in m/s, not m/min.
45 minutes is 2700 seconds.
That means that the displacement is
Δx = (.90)(2700) so
Δx = 2430 m
Now we plug that in to find work, along with the given Force:
W = 40(2430) so
W = 97200 J (and that is not the correct number of sig fig's but I have a feeling you're not too into that in class, because if you were, the 40 N would be expressed as 40.0 or 4.0 × 10¹)
how much of the electro magnetic spectrum is visible to us
Answer:
The entire rainbow of radiation observable to the human eye only makes up a tiny portion of the electromagnetic spectrum – about 0.0035 percent. This range of wavelengths is known as visible light.
Explanation:
Please Mark me brainliest
How did the current change when the circuit was initially closed in Part 2 of this exercise? Explain your answer by referencing Panel 1 and the definitions of a capacitor and of current.
Answer:
Some current is lost.
Explanation:
Change occur in the current when the circuit was initially closed because in a closed circuit the current moves from the start towards the end of the circuit through various resistors. There is heat produced in the wire when the current flows through the circuit. Due to this heat, some of the current is lost during on his own way. Capacitor is a device used to store an electric charge, having of one or more pairs of conductors separated by an insulator. while on the other hand, electric current is a stream of charged particles, such as electrons moving through conductor or space.
A fuse in an electric circuit is a wire that is designed to melt, and thereby open the circuit, if the current exceeds a predetermined value. Suppose that the material to be used in a fuse melts when the current density rises to 540 A/cm2. What diameter of cylindrical wire should be used to make a fuse that will limit the current to 0.57 A
Answer:
0.0366 m
Explanation:
We are given;
Current density; J = 540 A/cm² = 540 × 10⁴ m
Current; I = 0.57 A
Now, formula for current density is;
J = I/A
Where A is area = πr²
Thus;
J = I/(πr²)
r = √(I/(Jπ))
r = √(0.57/(540π))
r = 0.0183 m
Diameter = 2 × radius
Diameter = 2 × 0.0183
Diameter = 0.0366 m
