Answer:
Graphite.
Explanation:
Graphite: "a gray crystalline allotropic form of carbon which occurs as a mineral in some rocks and can be made from coke. It is used as a solid lubricant, in pencils, and as a moderator in nuclear reactors."
A skater of mass 60 kg has an initial velocity of 12 m/s. He slides on ice where the frictional force is 36 N. How far will the skater slide before he stops?
Answer:
d = 120 [m]
Explanation:
In order to solve this problem, we must use the theorem of work and energy conservation. Where the energy in the final state (when the skater stops) is equal to the sum of the mechanical energy in the initial state plus the work done on the skater in the initial state.
The mechanical energy is equal to the sum of the potential energy plus the kinetic energy. As the track is horizontal there is no unevenness, in this way, there is no potential energy.
E₁ + W₁₋₂ = E₂
where:
E₁ = mechanical energy in the initial state [J] (units of Joules)
W₁₋₂ = work done between the states 1 and 2 [J]
E₂ = mechanical energy in the final state = 0
E₁ = Ek = kinetic energy [J]
E₁ = 0.5*m*v²
where:
m = mass = 60 [kg]
v = initial velocity = 12 [m/s]
Now, the work done is given by the product of the friction force by the distance. In this case, the work is negative because the friction force is acting in opposite direction to the movement of the skater.
W₁₋₂ = -f*d
where:
f = friction force = 36 [N]
d = distance [m]
Now we have:
0.5*m*v² - (f*d) = 0
0.5*60*(12)² - (36*d) = 0
4320 = 36*d
d = 120 [m]
What is the form of energy that our eyes can detect?
A. Sound Energy
B. Chemical Energy
C. Light Energy
D. Thermal Energy
Answer: C. Light energy.
Explanation:
6. A total of 135 J of work is done on a gaseous refrigerant as it undergoes compression. If
the internal energy of the gas increases by 114 J during the process, what is the total amount
of energy transferred as heat? Has energy been added to or removed from the refrigerant as
heat?
Answer:
Eh = 21 [J]
Removed as heat.
Explanation:
This is a case of energy conservation, we have to take into account the energies that go in and out of the system. In this case, 135 [J] of energy are entered in the form of work of the compressor to the chamber where the refrigerant is compressed, now of these 135 [J] 114 [J] were used as internal energy, this internal energy is used to increase the pressure and temperature of the refrigerant.
In this way the rest of the energy of the 135 [J] was lost in the form of heat to determine this loss of energy, we simply perform the arithmetic subtraction.
Eh = 135 - 114 = 21 [J]
Eh = 21 [J]
What, exactly, is moving across the medium?
Answer:
So waves are everywhere. But what makes a wave a wave? What characteristics, properties, or behaviors are shared by the phenomena that we typically characterize as being a wave? How can waves be described in a manner that allows us to understand their basic nature and qualities?
A wave can be described as a disturbance that travels through a medium from one location to another location. Consider a slinky wave as an example of a wave. When the slinky is stretched from end to end and is held at rest, it assumes a natural position known as the equilibrium or rest position. The coils of the slinky naturally assume this position, spaced equally far apart. To introduce a wave into the slinky, the first particle is displaced or moved from its equilibrium or rest position. The particle might be moved upwards or downwards, forwards or backwards; but once moved, it is returned to its original equilibrium or rest position. The act of moving the first coil of the slinky in a given direction and then returning it to its equilibrium position creates a disturbance in the slinky. We can then observe this disturbance moving through the slinky from one end to the other. If the first coil of the slinky is given a single back-and-forth vibration, then we call the observed motion of the disturbance through the slinky a slinky pulse. A pulse is a single disturbance moving through a medium from one location to another location. However, if the first coil of the slinky is continuously and periodically vibrated in a back-and-forth manner, we would observe a repeating disturbance moving within the slinky that endures over some prolonged period of time. The repeating and periodic disturbance that moves through a medium from one location to another is referred to as a wave.
Hope That Helps!!
Explanation:
if 8000cm3 of liquid drains off an hour glass in one hour, what is the flow rate of water from the clock
Answer:
8000cm³/hr
Explanation:
Given parameters:
Volume of the liquid draining off per hour = 8000cm³
Time taken to drain off = 1hr
Unknown:
Flow rate = ?
Solution:
Flow rate is the volume of fluid that passes per unit of time.
Flow rate = [tex]\frac{volume of fluid}{time taken}[/tex]
Flow rate = [tex]\frac{8000cm^{3} }{1hr}[/tex]
Flow rate = 8000cm³/hr
A student tries to measure the period of a pendulum that is already swinging
left and right. At the moment when the pendulum is fully to the left, she
counts 'One' and starts a stopwatch. She counts successive swings each time
that the pendulum returns to the left. When she counts ‘Ten' she stops the
stopwatch, and sees that it reads 12.0 s.
a. What was her mistake?
______________________________________________________________
b. What is the period of swing of this pendulum?
______________________________________________________________
c. In this particular experiment, explain the likely effect of her reaction time
on her answer.
Answer:
a. The student's mistake was that the student did not swing the pendulum and start the watch at the same time.
b. 1.2 s per swing.
c. The likely effect of her reaction time is that they will should subtract two seconds off the time.
Explanation:
The pupil made the error of not simultaneously starting the watch and swinging the pendulum.
What is pendulum?Pendulum is defined as a body that is suspended from a fixed point and moves back and forth while being pulled by gravity. The pendulum is used to gauge the gravitational pull because the force of gravity causes it to swing back toward its average position. A pendulum's time period can be used to tell the time because it is constant.
The swing of the pendulum is 1.2 sec. per swing. They should take two seconds off the timing due to her presumably slow reaction time. A pendulum's total time should be divided by the quantity of oscillations in order to determine its time period. When compared to a pendulum with a shorter string, the one back and forth cycle of a longer-stringed pendulum requires more time to complete.
Thus, the pupil made the error of not simultaneously starting the watch and swinging the pendulum.
To learn more about pupil, refer to the link below:
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A car accelerates from 20 m/s to 80 m/s in 5 seconds. What is the
average acceleration of the car?
a 20 m/s2
b 12 m/s2
C 4 m/
d 16 m/s2
Answer:
12m/s2
Explanation:
:D (just a smiley, not answer d)
Is a ball a wheel and axle if so how do you calculate the Mechanical Advantage of the ball? If not what kind of simple machine is a ball?
Cellular respiration takes place in the mitochondria of cells.
Answer:
True
Because mitochondria is the powerhouse of the cell.
Explanation:
Hope this helps you
Answer:
True
Explanation:
When a toy car is moving across a flat surface, what forces are acting on it (gravity, tension, spring, friction,air,normal,applied)?
Answer:
I believe gravity is acting on it
If the density of water is 1000 kg/m², what is the pressure at the bottom of a swimming pool 2m
deep when it is full of water?
The pressure at the bottom when the given tank is full of water will be 19600 Pa.
Pressure can be calculated by the formula,
[tex]\bold {P = \rho h g}[/tex]
Where,
P- pressure = ?
[tex]\bold {\rho}[/tex] - density of water = 1000 kg/m²
h - height of water = 2 m
g - gravity acceleration = 9.8 m/s
Put the values in the formula
[tex]\bold {P = 2 \times 1000 \times 9.8} \\\\\bold {P = 19600\ Pa}[/tex]
Therefore, the pressure at the bottom when the given tank is full of water will be 19600 Pa.
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which change to a circuit is most likely to increase it electrical power
A: increase it's current and increase it's voltage
B: decrease it's current and increase it's voltage
C: decrease it's current and decrease it's voltage
D: increase it's current and decrease it's voltage
Answer:
A................
Explanation:
Hope this helps you
A. increase it's current and increase it's voltage
Explanation:
What is the difference between physical & chemical changes?
Slate whether each is an example of a Physleat (P) or Chemteal (C) property
1. Arock's density
2. boiling point of Gatorade
3. ability of an old car to rust
4. red color of a pe apple
S ability of wood to ignite
8. bitler taste of a lemon
7. melting point of wax
8. hardness of marble
9. Luster (shininess) of gold
boiling point Gatoride
Which of the following is an example of a luminous object?
Dog
Tree
Candle
Moon
Answer:
Candle
Explanation:
The moon is an illuminated object, while a candle is a luminous object!
Answer:
Candle
Explanation:
I just took the test
An object with an initial speed of 4.0 m/s accelerates uniformly at 2.0 m/s^2
in the direction of its motion for a distance of 5.0 meters. What is the final
speed of the object?
What will happen if we increase the friction on a roller coaster?
A. The speed of the roller coaster will increase.
B. The speed of the roller coaster will decrease
C. The speed of the roller coaster will remain constant.
D. The roller coaster will fly away
Answer: B. The speed will decrease.
Explanation:
When you ride a roller coaster, the wheels rub/scrape the rails, creating heat as a result of friction. And friction will slow you down. So increasing the friction on a roller coaster would slow it down.
Answer:
B
Explanation:
Friction opposes motion therefore reducing motion
Why do we use insulators if they prevent the flow of electricity?
Answer:
letterman is shooting the kids
We use insulators to avoid being electrocuted. electricians use rubber gloves to avoid shock. Cables are insolated with rubber so you can hold them without getting shocked even if it is plugged in.
1.A runner has a displacement of 20 meters in 5 seconds, what is his velocity
during this time?
Answer:
The required velocity of runner is 4m/s.
A group of athletes are trying to turn a large wheel and axle to move a stone. What can they do to move the wheel with less effort?
The diagram below shows the velocity vectors for two cars that are moving relative to each other.
From the frame of reference of car 1, what is the velocity of car 2?
Answer:
The answer is "[tex]5 \ \frac{m}{s} \ west[/tex]"
Explanation:
[tex]\to \vec{V_1} = (25 \frac{m}{s}) (\hat{-i})\\\\\to \vec{V_2} = (20 \frac{m}{s}) (\hat{-i})\\\\[/tex]
velocity of car | respect to car :
[tex]\to \vec{V_{12}} = \vec{V_1} - \vec{V_2}\\\\[/tex]
[tex]=\vec{-25} \hat{i}+ \vec{20} \hat{i}\\\\= 5 \ \frac{m}{s} \ west[/tex]
Answer:
70 m/s east
Explanation:
Finding the area of a trapezoid on a velocity versus time graph will tell you
the ——————
of an object.
A. displacement
B. acceleration
C. velocity
D. distance
How do you measure the wavelength of wave?
Explanation:
by finding the distance between two successful crest
Answer:
the wavelength can be measured as the distance from crest to crest or from trough to trough , the wavelength of a wave can be measured as the distance from a point on a wave to the corresponding point on the next cycle of the wave.
Explanation:
A battery and a resistor are wired into a circuit. The resistor dissipates 0.30 W. Now two batteries, each identical to the original one, are connected in series with the resistor. What power does it dissipate?
Answer:
1.2 W
Explanation:
Let the value of resistance be R , emf of battery be E
current i = E / R
power = i² R
= E² x R / R²
= E² / R
Given
E² / R = .30
when two batteries are connected
Total emf = 2E
current = 2E / R
Power = ( 2E / R )² x R
= 4 E² / R
= 4 x .30
= 1.2 W .
What is a super dense gravitationally collapsed mass from which no light
can escape called?
1) neutron star
2) pulsar
3) supernova
4) black hole
Se lanza una pelota y regresa al punto de partida 2.5 s después ¿Que altura máxima alcanzara? ¿a que altura se hallaba 1 segundo después del lanzamiento?
Answer:
a) [tex] y_{max} = 7.7 m [/tex]
b) y = 7.4 m
Explanation:
a) La altura máxima que alcanza la pelota se puede encontrar usando la siguiente ecuación:
[tex] y_{max} = y_{0} + v_{0y}t - \frac{1}{2}gt^{2} [/tex] (1)
En donde:
[tex]y_{0}[/tex]: es la altura inicial = 0
[tex]v_{0y}[/tex]: es la velocidad inicial en y
g: es la gravedad = 9.81 m/s²
t: es el tiempo
Primero debemos encontrar la velocidad inicial en y:
[tex] v_{fy} = v_{0y} - gt [/tex]
Sabiendo que la velocidad final en y es igual a cero (en la altura máxima), y con t = 1.25 s (la mitad del tiempo total) tenemos:
[tex] v_{0y} = gt = 9.81 m/s^{2}*1.25 s = 12.3 m/s [/tex]
Ahora, podemos encontrar la altura máxima:
[tex] y_{max} = v_{0y}t - \frac{1}{2}gt^{2} = 12.3 m/s*1.25 s - \frac{1}{2}9.81 m/s^{2}*(1.25 s)^{2} = 7.7 m [/tex]
b) Podemos encontrar la altura cuando t = 1 s con la misma ecuación (1):
[tex]y_{max} = y_{0} + v_{0y}t - \frac{1}{2}gt^{2} = 12.3 m/s*1 s - \frac{1}{2}9.81 m/s^{2}*(1 s)^{2} = 7.4 m[/tex]
Por lo tanto, la pelota se encontraba a 7.4 m luego de 1 segundo despúes del lanzamiento.
Espero que te sea de utilidad!
with what force will the a car hit a tree if the car has a mass of 3,000 kg and a acceleration of 2m/s^2
Answer:
The answer is 6000 NExplanation:
The force acting on an object given it's mass and acceleration can be found by using the formula
force = mass × acceleration
From the question we have
force = 3000 × 2
We have the final answer as
6000 NHope this helps you
Just like Coke is a type of soda, __________ is a type of ___________.
A.concentration,.equilibrium
B..equilibrium, concentration
C.diffusion, osmosis
D.osmosis. diffusion
Answer:
osmosis diffusionExplanation:
ok it's correct
In which image below is the angle of refraction the greatest?
Answer:
Explanation:
Angle of refraction is the angle made by refracted ray with the normal at the point of incidence . In this figure , refracted ray has been shown by line having arrow-head . Normal has been shown by broken line .
We observe that in figure D , angle made by refracted ray with normal is greatest . So figure D is the answer.
The image where the angle of refraction is the greatest is the image D
What is the angle of refraction?The angle of refraction is the angle that the refracted ray made with the x-axis.
The higher the angle between the refracted ray and the x-axis, the higher the angle of refraction and vice versa.
From the given diagram, we can see that the image where the angle of refraction is the greatest is the image D
Learn more on angle of refraction here: https://brainly.com/question/15838784
Momentum is a product of mass and....?
Answer:
Momentum is a product of mass and velocity.
Explanation:
Hope this helps you
Crown me as brainliest:)
Describe Kinetic Energy.