Answer:
1/2 m u^2 initial Kinetic Energy of body
m g h Potential Energy body attains as it rises to height
1/2 m u^2 = m g h conversion of KE to PE
h = u^2 / ( 2 g)
How many free electrons are there in 2.55 cm^ ^ 3 of pure Silicon Note N = Vp and rho = 1.54 free electrons / cm ^3
A: 3.93 x 10^20 free electrons
B: 6.32 x 10^20 free electrons
C: 3.93 x 10^22 free electrons
D: 6.32 x 10^2× free electrons
Answer:
C: 3.93 x 10^22 free electrons
Explanation:
The no. of free electrons can be found out using the following formula:
[tex]N = V\rho\\[/tex]
where,
N = No. of free electrons = ?
V = Volume = 2.55 cm³
ρ = density of electrons = 1.54 x 10²² free electrons/cm³
Therefore, using these values in the equation, we get:
[tex]N = (2.55\ cm^3)(1.54\ x\ 10^{22}\ free\ electrons/cm^3)\\[/tex]
N = 3.93 x 10²² free electrons
Therefore, the correct option is:
C: 3.93 x 10^22 free electrons
The moist bread becomes mouldy after a few days when it is left in a container with a cover. Which of the following conditions favour the growth of the fungus?
Answer: Moisture and food (bread)
Explanation:
Mould grows best in humid, damp air/wet conditions.
Since the bread is moist it will provide humidity for the mould as well as food.
A container with a cover would not be a favoring condition as mould needs oxygen to grow and survive.
A polythene rod may be charged by rubbing it with a cloth while being held in the hand but a metal rod cannot be charged in a similar way. Explain why
Answer:
Explanation:
This is because polythene rod is an insulator , therefore when it is rubbed with a cloth , electrons move easily therefore making it charged but
Metal rod is a conductor, it conduct heat . Therefore, their atoms have electrons that is constantly in motion. Therefore rubbing it with a cloth will make any difference in making it charged because it have very huge number of stable electrons which will not allow more electrons to move through them.
Which statement is correct about waves?
A. All waves move at the same speed in any
medium.
B. Waves carry the energy but do not carry the matter.
C. Waves must always move from one place to another.
D. Sound waves have more energy than light waves.
Answer:
b is the correct answer
Explanation:
Which statement describes the energy transformation that occurs when a person eats a sandwich to gain energy for a long hike?
A. Electrical energy stored in the molecules of the sandwich is transformed into chemical energy.
B. Kinetic energy stored in the bonds of the molecules of the sandwich is transformed into chemical energy.
C. Thermal energy stored in the molecules of the sandwich is transformed into kinetic energy.
D. Chemical energy stored in the bonds of the molecules of the sandwich is transformed into kinetic energy.
D. Chemical energy stored in the bonds of the molecules of the sandwich is transformed into kinetic energy. This statement describes the energy transformation that occurs when a person eats a sandwich to gain energy for a long hike
What is Law of energy conservation ?
Law of energy conservation states that energy can neither be created nor be destroyed and can only transform from one form to other form.
From Law of energy conservation we can say that Digestion starts from that very point when we put food in our mouth so the moment you eat the sandwich, it starts getting digested and when it reaches the stomach ,your body converts its chemical energy into the movement of your muscles.
hence , correct option is :
D. Chemical energy stored in the bonds of the molecules of the sandwich is transformed into kinetic energy.
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A child drops a bouncy ball. Each time it bounces, it reaches a lower height until it eventually
stops. Describe the energy transfers and explain why the ball lowered in height
Answer:
the ball's was lowered because of the gravitational force and because of the friction force's
a.
[tex]x + y = 0 \\ y = {x}^{2} + 2xy[/tex]
can any one tell this answer with dafination and all steps
Answer:
The system has two solutions:
(1, -1) and (0, 0)
Explanation:
We have the system of equations:
x + y = 0
x = x^2 + 2*x*y
To solve this, the first step is to isolate one of the variables in one of the equations, I will isolate x on the first one.
x = -y
Now we can replace this on the other equation, to get:
x = x^2 + 2*x*y
(-y) = (-y)^2 + 2*(-y)*y
Now we can solve this equation for y.
-y = y^2 - 2*y^2
-y = -y^2
y^2 - y = 0
We can solve this using the Bhaskara's formula:
The solutions are then:
[tex]y = \frac{-(-1) \pm \sqrt{(-1)^2 - 4*1*0} }{2*1} = \frac{1 \pm 1}{2}[/tex]
Then the two possible solutions are:
y = (1 + 1)/2 = 1
and
y = (1 - 1)/2 = 0
Suppose that we take the first one, y = 1.
Then the solution for x is given by "x = -y"
Then:
x = -1
This means that one solution of the system is (-1, 1)
If we take the other solution for y, y = 0
The value of x will be:
x = -y = -0 = 0
Then another solution of the system is (0, 0)
Describe the crust (in more than 1 sentence). Include a discussion of how the temperature changes on the crust.
Solution :
Crust
In the field of geology, the crust may be defined as the outermost solid shell of a planet. It forms the topmost outer hard layer of the earth surface. Earth has three layers. They are the crust, mantle and the core.
When we go deeper and deeper inside the earth's crust, the temperature rise. In the crust, on the surface of the earth, the temperature is normal and is atmospheric. As we go deep down the core, the temperature rise and it is highest at the core where all the rock and the iron is in the form of the molten lava.
According to the Geologist, beneath the earth's crust, for every mile we go inside the temperature rises by 15 degree Fahrenheit.
( Science) Do you think seismographs predict earthquakes or measure earthquakes? Explain your answer.
Answer:
No. Neither the USGS nor any other scientists have ever predicted a major earthquake. We do not know how, and we do not expect to know how any time in the foreseeable future. USGS scientists can only calculate the probability that a significant earthquake will occur in a specific area within a certain number of years.
Answer:
No. Neither the USGS nor any other scientists have ever predicted a major earthquake. We do not know how, and we do not expect to know how any time in the foreseeable future. USGS scientists can only calculate the probability that a significant earthquake will occur in a specific area within a certain number of years.
Explanation:
A tank of water is 4m deep. How deep does it appear when seen normally?
Answer:
The tank appears to be 3 m deep only. Step by step solution by experts to help you in doubt clearance & scoring excellent marks in exams.
can em waves travel at the speed of light?
true or false
Answer:
f nothing can move faster than spped of light.
Explanation:
Tammy is a forensic investigator examining a body at a crime scene. She notes that the body is stiff but still flexible. What does she know about the time of death?
Answer:
It happened less than 8 hours ago.
Explanation:
Over the first eight hours, the body begins to stiffen but is still flexible.
what is nylon?
answer
Answer:
Nylon is a generic designation for a family of synthetic polymers composed of polyamides.
Explanation:
the basic units involved in netwon?
Answer:
kilogram metre per second square
Which of the following wave on the electromagnetic spectrum has more energy? Ultraviolet or x-rays?
Answer: ultraviolet
Explanation:
Please someone help me. I don't know how to do this and it's due tonight.
Answer:
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What is the Average Depth of the ocean?
Answer:
The average depth of the ocean is about 12,100 feet.
Explanation:
A bus contains a 1500 kg flywheel (a disk that has a 0.600 m radius) and has a total mass of 10,000 kg.
(a) Calculate the angular velocity the flywheel must have to contain enough energy to take the bus from rest to a speed of 20.0 m/s, assuming 90.0% of the rotational kinetic energy can be transformed into translational energy.
(b) How high a hill can the bus climb with this stored energy and still have a speed of 3.00 m/s at the top of the hill? Explicitly show how you follow the steps in the Problem-Solving Strategy for Rotational Energy.
Answer:
Explanation:
moment of inertia of flywheel = 1/2 m R²
= .5 x 1500 x .6²
= 270 kg m²
If required angular velocity be ω
rotational kinetic energy = 1/2 I ω²
= .5 x 270 x ω² = 135 ω²
kinetic energy of bus when its velocity is 20 m/s
= 1/2 x 10000 x 20²
= 2000000 J
Given 90 % of rotational kinetic energy is converted into bus's kinetic energy
135 ω² x 0.9 = 2000000 J
ω²=16461
ω = 128.3 radian /s
b )
Let the height required be h .
Total energy of bus at the top of hill = mgh + 1/2 m v²
m ( gh + .5 v²)
= 10000 ( 9.8h + .5 x 3²)
From conservation of mechanical energy theorem
10000 ( 9.8h + .5 x 3²) = 2000000
9.8h + .5 x 3² = 200
9.8h = 195.5
h = 19.95 m .
Which is a leading theory for the formation of fossil fuels?
Answer:
The most widely accepted theory for the formation of fossil fuel is that fossil fuel was formed over time from decaying organic matter. Organisms died and were buried in the ground millions of years ago.
Explanation:
g00gle answer! so change it up a little :P
hope this helps :)
लाइ फ्युजका
4
Why MCB is called the developed form of fuse? Give the reason
Miniature circuit breakers is called the developed form of fuse because MCBs are more sensitive to current than fuses. They immediately detect any abnormality and switch off the electrical circuit automatically. This prevents any permanent damage to electrical appliances and human beings
True or false. There is only an induced voltage in a coil of wire if the magnetic flux through the coil of wire changes.
wheel and excel has co-axial cylinder. true or false
Answer:
True, wheel and excel has co-axial cylinder. true or false.
You can follow me to get more answer.
Answer:
true
Explanation:
yes they have two com xial cylinder and they work together
List five objects in your daily life that produce sounds with a high pitch and five that produce sounds with a low pitch.
Answer:
Explanation:
High pitch:
-birds chirping
-nails on a chalkboard
-flies buzzing
-children squealing
-whistle
Low pitch:
-thunder
-dogs barking
- earthquakes
- bass drum,
-cannon shot,
5 example of high pitch sound
baby crying , whistle , school bell , fire alarm , chirping of birds
5 example of low pitch sound
thunder , drum , earthquake , generator , animal roar
What is a pitch ?
It is the effect or sensation produce in brain due to sound of some particular frequency
5 example of high pitch sound
baby crying , whistle , school bell , fire alarm , chirping of birds
5 example of low pitch sound
thunder , drum , earthquake , generator , animal roar
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Mainly need help with part A. No links, thanks!
Answer:
R = 4Ω
Explanation:
If we have two resistors with resistances R1 and R2 in series the total resistance is R = R1 + R2
If the resistances are in parallel, the total resistance is given by:
1/R = 1/R1 + 1/R2.
First, we have a resistor with R1 = 1.5Ω
This resistor is connected in series with a parallel part (let's find the resistance of this parallel part), in one branch we have two resistors in series with resistances:
R2 = 8Ω and R3 = 4Ω
Because these are in series, the resistance of that branch is:
R = 8Ω + 4Ω = 12Ω
In the other branch, we have a single resistor of R4 = 4Ω
The resistance of the parallel part is:
1/R = 1/12Ω + 1/4Ω = 1/12Ω + 3/12Ω = 4/12Ω = 1/3Ω
1/R = 1/3Ω
R = 3Ω
Then we have a resistor (the first one, R1 = 1.5Ω) in series with a resistor of 3Ω.
Then the total resistance is:
R = 1Ω + 3Ω = 4Ω
Which one of the following statements is true: The reactive power is the power dissipated in the form of heat by the network. The reactive power is the power delivered to a load without considering the effects of the power-factor angle of the load. The apparent power is the power delivered to a load without considering the effects of the power-factor angle of the load. The real power is the power associated with reactive elements that provides a measure of the energy associated with setting up the magnetic and electric fields.
Answer:
The apparent power is the power delivered to a load without considering the effects of the power-factor angle of the load
Explanation:
If I and V are the current and voltage across the load, the apparent power, = IV
Since,
apparent power = active power + reactive power
active power = IVcosФ
reactive power = IVsinФ
So, IV = IVcosФ + IVsinФ
where I = current, V = voltage and Ф = power factor angle.
We see that the apparent power is the product of the current, I and the Voltage, V without considering the power factor angle of the load.
So, the apparent power is the power delivered to a load without considering the effects of the power-factor angle of the load.
based on the magnetic field lines shown what is the orientation of the mystery magnet ?
Se tiene un objeto que oscila con MAS. Si la amplitud del movimiento es de 15 cm y el periodo es de 2 seg, encontrar las magnitudes de la velocidad y la aceleración cuando: a) x= 0 cm b) x=7,5 cm Por favor, ayúdenme es para hoy :c
Answer:
a) v = 0, a = - 15 pi²
b) v = - 40.8 cm / s, a = -74.2 cm / s
Explanation:
the simple harmonic motion is described by the expression
x = A cos (wt + Ф)
in that case they indicate the amplitude of the movement
A = 15 cm
angular velocity and period are related
w = 2π / T
w = 2π/ 2
w = π rad / s
speed is defined by
v = dx / dt
v = -A w sin (wt + Ф)
acceleration is defined by
a = dv / dt
a = - A w² cos (wt + Ф)
In order to evaluate this expression we must know the value of the phase constant (Ф) that meets the initial conditions, the most common thing is that the system is released, v = 0 for y = 0 s, let's use the speed equation
v = -A w sin (0+ Ф)
for this expression to be zero, the sine must be zero, so
Ф= 0
now let's write the equations for our case
v = - 15 π sin (π t)
a = - 15 π² cos (π t)
a) for x = 0
v = 0
a = - 15 pi²
b) for x = 7.5 cm
Let's find out how long it takes to get to this position
x = 15 cos (π t)
7.5 / 15 = cos π t
pi t = cos⁻¹ 0.5
t = 1.047/π
don't forget that the angles are in radians
t = 0.333 s
now let's look for speed and acceleration
v = - 15 π sin (π 0.333)
v = - 40.8 cm / s
a = - 15 π² cos (π 0.333)
a = -74.2 cm / s
Help science 70 points
first. this is only worth 38 points second it's B
Answer:
Explanation:
5. If a spring with a 40 N/m spring constant is used to push a 10 kg ball to a speed of 2 m/s,
how much must the spring have been compressed assuming no energy is lost?
By compressing the spring a distance x (in m), you are storing 1/2 k x ² (in J) of potential energy, which is converted completely into kinetic energy 1/2 m v ², where
• k = 40 N/m = spring constant
• m = 10 kg = mass of the ball
• v = 2 m/s = ball's speed (at the moment the spring returns to its equilibrium point)
So we have
1/2 k x ² = 1/2 m v ²
x = √(m/k v ²) = √((10 kg) / (40 N/m) (2 m/s)²) = 1 m
A piece of stone weigh 90 grams. When it lowered in measuring cylinder containing water. The final volume of water is 30 cubic centimetres. Calculate the density of the stone.
Answer:
3 gm / cm^3
Explanation:
Density = weight / volume
90 / 30 = 3 gm/cm^3