Answer:
option A is correct answer of this question
Explanation:
=> it allows us to see with candles and kerosene lamps
hope it helps
A police officer uses a radar gun that emits electromagnetic waves with a frequency of 10.525 GHz (1.0525 1010 Hz). Assume the police officer is at rest, and is aiming the radar gun at vehicles traveling either directly toward, or directly away from, the radar gun. Assume the speed limit is 110 km/h, as it is on many Canadian highways. The police officer observes reflected waves that have a frequency of 2460 Hz below the frequency of the emitted waves.
Required:
a. At what speed is the car moving?
b. Choose the two correct statements about this situation.
1. The car is moving toward the police officer.
2. The car is moving away from the police officer.
3. The police officer should not cite the driver for speeding.
4. The police officer should cite the driver for speeding.
Answer:
Explanation:
For Doppler effect in radar the formula is as follows
Δf = f₀ x 2v /c
Δf is change in frequency in reflected wave , f₀ is original frequency , v is velocity of source and c is velocity of right .
Δf = 2460 Hz , f₀ = 1.0525 x 10¹⁰ Hz , v = ? c is velocity of light .
2460 = 1.0525 x 10¹⁰ x 2 v / 3 x 10⁸
2460 = 105.25 x 2 v / 3
v = 2460 x 3 / (105.25 x 2 )
v = 35 .06 m /s .
(b)
Since the observed frequency is less , the source is moving away from the observer .
option (2) is correct .
A human body consists of
Answer:
60% of the human adult body is water. According to H.H. Mitchell, Journal of Biological Chemistry 158, the brain and heart are composed of 73% water, and the lungs are about 83% water. The skin contains 64% water, muscles and kidneys are 79%, and even the bones are watery: 31%.
Explanation:
When you measure the mass of an object you are also measuring its what
Here ya go-!
Mass is both a property of a physical body and a measure of its resistance to acceleration (a change in its state of motion) when a net force is applied. An object's mass also determines the strength of its gravitational attraction to other bodies. The basic SI unit of mass is the kilogram (kg).
(um im sorry if its wrong-)
a box is slides down a slope
Answer:
120 N
Explanation:
From the question given above, the following data were obtained:
Angle (θ) = 35°
Mass (m) = 15 Kg
Acceleration due to gravity (g) = 9.8 m/s²
Normal force (N) =?
The normal force acting on the object can be obtained as:
N = mg × Cosθ
N = 15 × 9.8 × Cos 35
N= 147 × 0.8192
N = 120 N
Therefore, the normal force acting on the object is 120 N
A cylindrical tank with radius 3 m is being filled with water at a rate of 2 m3/min. How fast is the height of the water increasing (in m/min)
Answer:
.0707 m / min
Explanation:
The computation is shown below:
= Flow of the volume ÷ crossectional area
A = π × r^2
= 9 π
= 28.27 m^2
so, the fast of the height of the water rise is
=(2 m^3 / min) ÷ 28.27 m^2
= .0707 m / min
what is the reason for timing more than one oscillation in a simple pendulum
Answer:
Time period is the time taken by the body to complete one oscillation and it is noted more than once to get accurate reading from averaging of all the observed values.
I need help with 5 please and thank you
Answer: A
Explanation:
Expository essay "Climate change in Fiji"
Answer: Climate change poses to the tourism development in Fiji islands. It shows the adverse effects of the changing climate and the dangers pose by the tourism activities and also pose a major hazard for the local people in the region. It also deals with the dangerous carbon emissions and CO2 effect on the landscape, food, water, energy.
The pacific is the world`s largest ocean with a surface area of 175 million sq km and constitutes for 40% of the planet`s waters. Located in the tropical latitudes, it covers more than half the globe`s circumference. Temperature of the surface water in the western tropical regions is always more than 28 ÌŠC over a depth of several hundred meters. This makes up the world`s storage of thermal energy for exchange with atmosphere. Here the interaction between atmosphere and ocean is most extreme and influences the climate not only regionally but planet-wide. The nations of the pacific are obscured human settlements absorbed in this vast fluid universe. The ocean is the most important factor controlling the environment and life.
PLEASE HELP ME WITH THIS ONE QUESTION
A tuning fork of 500 Hz is struck in a room with a speed of sound of 340 m/s. What is the distance between a point of rarefaction and the next compression point, in the resulting sound?
Answer:
0.34 m
Explanation:
From the question,
v = λf................ Equation 1
Where v = speed of sound, f = frequency, λ = Wave length
Make λ the subject of the equation
λ = v/f............... Equation 2
Given: v = 340 m/s, f = 500 Hz.
Substitute these values into equation 2
λ = 340/500
λ = 0.68 m
But, the distance between a point of rarefaction and the next compression point, in the resulting sound is half wave length
Therefore,
λ/2 = 0.68/2
λ/2 = 0.34 m
Hence, the distance between a point of rarefaction and the next compression point, in the resulting sound is 0.34 m
1. Why is the flow of electrons from A to B?
2. What's the difference between flow of current & flow of electrons and why ar they opposite?
1. because A is more negative than B. A is -1000 V (we can imagine that A has excess 1000 electrons), in other, B which +3000 V can be assume that B need 3000 elctrons to be neutral. So, the electron will flow from A to B.
2. Electrons being negatively charged flow from the negative terminal to the positive terminal of the voltage source. So, the actual direction of current should be from negative to positive terminal. However, the conventional direction had already been established. So, the current flow is considered in the direction opposite to the direction of flow of electrons. (from topperlearning dot com)
An elevator motor in a high-rise building can do 3500 kJ of work in 5 min. Find the power developed by the motor. Explain if you can plz
Answer:
P = 11666.6 W
Explanation:
Given that,
Work done by the motor, W = 3500 kJ
Time, t = 5 min = 300 s
We need to find the power developed by the motor. Power developed is given by :
[tex]P=\dfrac{E}{t}\\\\P=\dfrac{3500\times 10^3}{300}\\\\P=11666.7\ W[/tex]
So, the required power is 11666.6 W.
1. Only about
% of water on Earth is fresh water that is readily available for human consumption.
a. less than 1
b. 5
c. more than 50
d. All water on Earth is fresh water and is easily accessible.
Answer:
Hey mate.....
Explanation:
This is ur answer....
a. Less than 1%3% of the earth's water is fresh. 2.5% of the earth's fresh water is unavailable: locked up in glaciers, polar ice caps, atmosphere, and soil; highly polluted; or lies too far under the earth's surface to be extracted at an affordable cost. 0.5% of the earth's water is available fresh water....
Hope it helps you,
Mark me brainliest plz....
Follow me! :D
Question:
1. Only about % of water on Earth is fresh water that is readily available for human consumption.
a. less than 1
b. 5
c. more than 50
d. All water on Earth is fresh water and is easily accessible
Answer:
a. less than 1
Will the 79 kg skier in the figure below slide down if f the coefficient of static friction is 0.25?
Answer:
Man will not slide down
Explanation:
Given:
Coefficient of static friction = 0.25
Angle = 13°
Computation:
Man will slide down if
tan13° > Coefficient of static friction
Tan 13 = 0.23
So,
0.23 < 0.25
So,
Man will not slide down
A cricketer lowers his hand while catching balls. Why?
Answer:
While catching a ball, a cricket player lowers his hands, because by doing so, he increases the time of catch. That is, the person increases the time to bring about a given change in momentum, and hence rate of change of momentum decreases. Thus, a small force is exerted by ball on the hands.
Explanation:
:)
Answer:
it is your answer....... if it is helpful plzz like and comment
(WILL MARK BRAINLIAST)( 1 answer question.. look the photo)
As the cars come closer together, the amount of potential energy in the system:
-Increases
-Decreases
-Stays the same
Answer:
increases
Explanation:
due to less speed
We can model a pine tree in the forest as having a compact canopy at the top of a relatively bare trunk. Wind blowing on the top of the tree exerts a horizontal force, and thus a torque that can topple the tree if there is no opposing torque. Suppose a tree's canopy presents an area of 9.0 m2 to the wind centered at a height of 7.0 m above the ground. (These are reasonable values for forest trees.)
Answer:
A,)FD= 114.1N
B)Torque=798.5Nm
Explanation:
We can model a pine tree in the forest as having a compact canopy at the top of a relatively bare trunk. Wind blowing on the top of the tree exerts a horizontal force, and thus a torque that can topple the tree if there is no opposing torque. Suppose a tree's canopy presents an area of 9.0 m^2 to the wind centered at a height of 7.0 m above the ground. (These are reasonable values for forest trees.)
If the wind blows at 6.5 m/s, what is the magnitude of the drag force of the wind on the canopy? Assume a drag coefficient of 0.50 and the density of air of 1.2 kg/m^3
B)What torque does this force exert on the tree, measured about the point where the trunk meets the ground?
A)The equation of Drag force equation can be expressed below,
FD =[ CD × A × ρ × (v^2/ 2)]
Where CD= Drag coefficient for cone-shape = 0.5
ρ = Density
Area of of the tree canopy = 9.0 m^2
density of air of = 1.2 kg/m^3
V= wind velocity= 6.5 m/s,
If we substitute those values to the equation, we have;
FD =[ CD × A × ρ × (v^2/ 2)]
F= [ 0.5 × 9.0 m^2 × 1.2 kg/m^3 ( 6.5 m/s/ 2)]
FD= 114.1N
B) the torque can be calculated using below formula below
Torque= (Force × distance)
= 114.1 × 7
= 798.5Nm
I need help with science:
Question 1: Chlorophyll makes some plants look yellow.
True
False
_________________________
Question 2:
Protozoa are a type of unicellular organisms.
True
False
__________________________________
Question 3:
Nerve cells carry oxygen to the body.
True
False
______________________________________
Question 4:
The__ is the basic unit of all living things.
Options:
nucleus
cell
___________________________
if you answer these all right:
( if u want brainlist's answer this question then ask another random question on your page so u can give me brainlist back, also i need to people to answer so i can chose one of you guys to give the brainlist's to, deal or no?)
no links and ill give good points so u better not steal them or ill report...
The microwaves produced inside a microwave have a wavelength of 12.0m and a frequency of 25Hz. At what speed do the microwaves travel in units of m/s ?
Answer: 300 m/s
Explanation:
The equation for finding wave speed is the wavelength times the frequency which would be
12.0mx 25hz=300m/s
Within which type of system is the total energy conserved?
A. Isolated
B. Connected
C. Closed
D. Open
The total energy is conserved within isolated system.
How is energy conserved in an isolated system?In an isolated system, there is no exchange of matter or energy with the surroundings. Therefore, the total energy within the system remains constant, meaning that energy is conserved within the system.
In contrast, in an open system, there can be an exchange of both matter and energy with the surroundings, so the total energy within the system is not necessarily conserved.
In a closed system, there can be an exchange of energy but not matter, so the total energy within the system is conserved as long as there is no work being done by or on the system. In a connected system, the term is not commonly used in the context of energy conservation.
Learn about isolated system here https://brainly.com/question/17580023
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A cart moves with negligible friction or air resistance along a roller coaster track. The cart starts from rest at the top of a hill of unknown height. It then goes down that first hill and up another circularly shaped hill of height 10 meters and radius 15 meters. The ride is designed so that the cart just barely loses contact with the track at the top of the second hill (10 meters above ground level). What is the height of the starting hill relative to ground
Answer:
hinit = 17.5 m
Explanation:
Assuming no friction present, the mechanical energy must be conserved, which means that at any point of the trajectory, the sum of the gravitational potential energy and the kinetic energy must keep the same.At the top of the hill, since it starts from rest, all the energy must be potential, and we can express it as follows:[tex]E_{o} = U_{o} = m*g*h_{init} (1)[/tex]
When the car arrives to the top of the second hill, as we know that it is lower than the first one, the energy of the car, must be part gravitational potential energy, and part kinetic energy.We can express this final energy as follows:[tex]E_{f} = U_{f} + K_{f} = m*g* h_{2} + \frac{1}{2} *m*v_{f} ^{2} (2)[/tex]
In order to find hinit, we need to make (1) equal to (2), and solve for it.In (2) we have the value of h₂ (10 m), but we still need the value of the speed at the top of the second hill, vf.Now, when the car is at the top of the hill, there are two forces acting on it, in opposite directions: the normal force (upward) and the weight (downward).We know also that there is a force that keeps the car along the circular track, which is the centripetal force.This force is just the net downward force acting on the car (it's vertical at the top), and is just the difference between the weight and the normal force.If the cart just barely loses contact with the track at the top of the second hill, this means that at that point the normal force becomes zero.So, the centripetal force must be equal to the weight.The centripetal force can be expressed as follows:[tex]F_{c} = m*\frac{v_{f} ^{2}}{R} (3)[/tex]
We have just said that (3) must be equal to the weight:[tex]F_{c} = m*\frac{v_{f} ^{2}}{R} = m*g (4)[/tex]
Simplifying, and rearranging, we can solve for vf², as follows:[tex]v_{f}^{2} = R*g (5)[/tex]
Replacing (5) in (2), simplifying and rearranging in (1) and (2) we finally have:[tex]h_{init} = h_{2} + \frac{1}{2} R = 10m + 7.5 m = 17.5 m (6)[/tex]
The amount of sliding friction depends on the
a. weight of the moving object and the type of surface that the
object slides across.
b. density and volume of the object.
c. acceleration and mass of the object.
d. density and mass of the object.
*help please
Answer:
c I think so do u know the formula for friction??friction? lkke kinetic friction
A student sets up a standing wave of wavelength 6 meters in a coiled spring by moving his hand up and down twice each second. What is the velocity of the wave?
Answer:
Velocity = 12 m/s
Explanation:
Given the following data;
Wavelength = 6 meters
Period = 0.5 seconds. This is due to the fact that the student is moving his hand up and down twice each second.
To find the velocity;
Velocity = wavelength * frequency
But, frequency = 1/period
Frequency = 1/0.5
Frequency = 2
Substituting the values into the velocity formula, we have;
Velocity = 6 * 2
Velocity = 12 m/s
Therefore, the velocity of the wave is 12 meters per seconds.
faraday's law states that the potential difference can be increased by... (choose all that apply)
1. using static electricity instead of current electricity
2. increase the number of coils, increase the strength of the magnet
3. using a bunch of small magnets
4. increasing the time used to power up an electromagnet
5. increase the speed of the magnet
Id say its the last option of the fourth option
Explanation:
Answer:
1:increase the number of coils, increase the strength of the magnet
2:increase the speed of the magnet
3: increasing the time used to power up an electromagnet
Explanation:
1). Increasing the number of turns of wire in the coil – By increasing the amount of individual conductors cutting through the magnetic field, the amount of induced emf produced will be the sum of all the individual loops of the coil, so if there are 20 turns in the coil there will be 20 times more induced emf than in one piece of wire.
2). Increasing the speed of the relative motion between the coil and the magnet – If the same coil of wire passed through the same magnetic field but its speed or velocity is increased, the wire will cut the lines of flux at a faster rate so more induced emf would be produced.
3). Increasing the strength of the magnetic field – If the same coil of wire is moved at the same speed through a stronger magnetic field, there will be more emf produced because there are more lines of force to cut.
how much force is needed to accelerate a 2500kg car at a rate of 4m/s2
Answer:
10,000 N
Explanation:
Using Newton's Second Law of Motion, Force = Mass*Acceleration.
Plugin 2500 kg for the mass and 4 m/s^2 for the acceleration.
Force = 2500 kg*4 m/s^2 = 10000 Newtons
(SI unit of force is Newtons)
Air plane travels 224 in 2 hours.
How fast was the plane traveling?
Answer:
112mph
Explanation:bugyg
A person holds a 0.300 kg pomegranate at the top of a tower that is 96m high. Another person holds a 0.800 kg melon next to an open window 32m up the tower
Complete question:
A person holds a 0.300 kg pomegranate at the top of a tower that is 96m high. Another person holds a 0.800 kg melon next to an open window 32m up the tower.
Calculate the gravitational potential energy of the pomegranate and melon.
Answer:
The gravitational potential energy of pomegranate is 282.24 J
The gravitational potential energy of melon is 250.88 J
Explanation:
Given;
mass of the pomegranate, m₁ = 0.3 kg
height of the pomegranate, h₁ = 96 m
mass of the melon, m₂ = 0.8 kg
height of the melon, h₂ = 32 m
The gravitational potential energy of pomegranate is calculated as;
P.E₁ = m₁gh₁
P.E₁ = 0.3 x 9.8 x 96
P.E₁ = 282.24 J
The gravitational potential energy of melon is calculated as;
P.E₂ = m₂gh₂
P.E₂ = 0.8 x 9.8 x 32
P.E₂ = 250.88 J
the one that answered this is correct so give him credit not me
Answer:
Complete question:
A person holds a 0.300 kg pomegranate at the top of a tower that is 96m high. Another person holds a 0.800 kg melon next to an open window 32m up the tower.
Calculate the gravitational potential energy of the pomegranate and melon.
The gravitational potential energy of pomegranate is 282.24 J
The gravitational potential energy of melon is 250.88 J
Given;
mass of the pomegranate, m₁ = 0.3 kg
height of the pomegranate, h₁ = 96 m
mass of the melon, m₂ = 0.8 kg
height of the melon, h₂ = 32 m
The gravitational potential energy of pomegranate is calculated as;
P.E₁ = m₁gh₁
P.E₁ = 0.3 x 9.8 x 96
P.E₁ = 282.24 J
The gravitational potential energy of melon is calculated as;
P.E₂ = m₂gh₂
P.E₂ = 0.8 x 9.8 x 32
P.E₂ = 250.88 J
the one that answered this is correct so give him credit not me
What instrument makes the slowest vibration? A drum? A whistle? A flute? Or a harmonica?
Answer:
A harmonica.
Explanation:
The structure of a harmonica is built in such a way that when the air is blown by the player in it, the air moves within the rectangular structure and making sound vibrations. Sound is heard when an object vibrates. The movement of this vibration creates sound waves, and these waves enter our ears in the form of music.
Therefore, the instrument that will make the slowest vibration among the given instrument will be the harmonica. Thus option D is correct.
Find the velocity of a dolphin that swims 55 m in 5.0 s.
Answer: 11 m/s
Explanation: velocity = distance /time = 55 m /5.0 s
Answer:40km/h
Explanation:
The statement "If a plant receives fertilizer,
then it will grow to be bigger than a plant
that does not receive fertilizer" is an
example of
A. an observation.
B. a hypothesis.
C. a theory.
A wave of frequency 500hz and wave length 50m is traveling into a medium, dertimine the speed of velocity of the wave. formula V=f×d.
Answer:
25000m/s
Explanation:
V=fd
V=(500)(50)
V=25000m/s
Ans
Sep 19, 2019 — Wave speed is the distance a wave travels in a given amount of time, such as the ... Wave speed is related to both wavelength and wave frequency. ... The equation for wave speed can be used to calculate the speed of a wave when both ... Frequency = SpeedWavelength or Wavelength = SpeedFrequency.
Explanation: