Answer:
Non-Ionizing Radiation From Wireless TechnologyRadiofrequency (RF) energy is a type of electromagnetic radiation. It is used to transmit signals carrying information in the form of radio waves. Radio waves are broadcast using a transmitter. When the radio waves reach a receiver, the signal is converted back into the information that was originally sent by the transmitter. When you talk on a cell phone, your cell phone acts as a transmitter and your voice is carried on radio waves to the person you are calling. Their phone acts as the receiver and converts the signal back into your voice. In addition to cell phones, other wireless devices such as radios, Wi-Fi routers, satellites, radars and pacemakers can send or receive RF energy waves.
A 20 kg truck drives in a circle of radius 4 m at 10m/s. What causes
the circular motion?
A. Normal Force
B. Friction
C. Tension
D. Gravity
Answer:
Normal force
Explanation:
The force is centipetral forceCalculating :-
Mass=m=20kgRadius=r=4mVelocity=10m/s=vWe know
[tex]\boxed{\sf F_c=\dfrac{mv^2}{r}}[/tex]
[tex]\\ \sf\longmapsto F_c=\dfrac{20(10)^2}{4}[/tex]
[tex]\\ \sf\longmapsto F_c=\dfrac{20(100)}{4}[/tex]
[tex]\\ \sf\longmapsto F_c=\dfrac{2000}{4}[/tex]
[tex]\\ \sf\longmapsto F_c=500N[/tex]
2. A person jogs 4.0 km in 32 minutes, then 2.0 km in 22 minutes, and finally 1.0 km in 16 minutes.
What is the jogger's average speed in km per minute?
Answer:
0.1 km/min
Explanation:
7 / 70 = 0.1km/min
An empty cardboard box falls from a high platform. Through the use of special equipment it was found that the energy of the cardboard box at the top of the fall was more than the energy of the box at the bottom of the fall. Explain.
Answer:
The mechanical energy of the cardboard box, M.E. = K.E. + P.E.
Where;
P.E. = The potential energy of the cardboard box = m·g·h
K.E. = The kinetic energy of the cardboard box = (1/2)·m·v²
Where;
m = Mass of the cardboard box
g = The (constant) acceleration due to gravity ≈ 9.81 m/s²
h = The height of the cardboard box
v = The velocity of the cardboard box
At the top of the fall, where h = The height of the platform = [tex]h_{platform}[/tex], and v = 0 (the box is initially at rest at the top), the M.E. is given as follows;
[tex]M.E._{top}[/tex] = P.E. + K.E. = m·g·[tex]h_{platform}[/tex] + (1/2) × m × 0² = m·g·[tex]h_{platform}[/tex]
However, at the bottom of the fall, the height of the box, h = 0, the velocity of the box, v = 0, therefore, the total energy at the bottom, after the box comes to rest, [tex]M.E._{bottom}[/tex] = 0
Therefore;
The total energy of the box at the top of the fall, .[tex]M.E._{top}[/tex] = m·g·[tex]h_{platform}[/tex] was more than the total energy of the box at the bottom of the fall,
[tex]M.E._{bottom}[/tex] = 0
Explanation:
Is velocity ratio of a machine affected by applying oil on it? Explain with reasons.
Answer:
when it comes to machines being Rusty oil is like the root loosener
A uniform, solid sphere of radius 2.50 cm and mass 4.75 kg starts with a purely translational speed of 3.00 m/s at the top of an inclined plane. The surface of the incline is 2.75 m long, and is tilted at an angle of 22.0∘ with respect to the horizontal. Assuming the sphere rolls without slipping down the incline, calculate the sphere's final translational speed v2 at the bottom of the ramp.
Answer:
The final translational seed at the bottom of the ramp is approximately 4.84 m/s
Explanation:
The given parameters are;
The radius of the sphere, R = 2.50 cm
The mass of the sphere, m = 4.75 kg
The translational speed at the top of the inclined plane, v = 3.00 m/s
The length of the inclined plane, l = 2.75 m
The angle at which the plane is tilted, θ = 22.0°
We have;
[tex]K_i[/tex] + [tex]U_i[/tex] = [tex]K_f[/tex] + [tex]U_f[/tex]
K = (1/2)×m×v²×(1 + I/(m·r²))
I = (2/5)·m·r²
K = (1/2)×m×v²×(1 + 2/5) = 7/10 × m×v²
U = m·g·h
h = l×sin(θ)
h = 2.75×sin(22.0°)
∴ 7/10×4.75×3.00² + 4.75×9.81×2.75×sin(22.0°) = 7/10 × 4.75×[tex]v_f[/tex]² + 0
7/10×4.75×3.00² + 4.75×9.81×2.75×sin(22.0°) ≈ 77.93
∴ 77.93 ≈ 7/10 × 4.75×[tex]v_f[/tex]²
[tex]v_f[/tex]² = 77.93/(7/10 × 4.75)
[tex]v_f[/tex] ≈ √(77.93/(7/10 × 4.75)) ≈ 4.84
The final translational seed at the bottom of the ramp, [tex]v_f[/tex] ≈ 4.84 m/s.
Derive the following equations. :a=u-v by t
A bus travelled 160 km in 4 hours, another bus travelled 175 km in 5 hours, which bus moved faster?
[tex]\boxed{\sf Speed=\dfrac{Distance}{Time}}[/tex]
For 1st bus:-Distance=160kmTime=4h[tex]\\ \sf\longmapsto Speed=\dfrac{160}{4}[/tex]
[tex]\\ \sf\longmapsto Speed=40km/h[/tex]
For 2nd busDistance=175kmTime=5h[tex]\\ \sf\longmapsto Speed=\dfrac{175}{5}[/tex]
[tex]\\ \sf\longmapsto Speed=35km/h[/tex]
Bus 1moved faster
any person for the job he applied Force moment or torque
Answer:
i think torque is the answer not confirmed
difference between uniform motion and non uniform motion
Answer:
Uniform motion is a type of motion that is characterized as the motion of an object wherein the object moves in a straight line and its velocity remains unchanged along that line, regardless of the duration of time, as it occupies equal distances at equal time interval and Non-uniform motion is described as the motion of an object wherein the object moves at different speeds and does not cover the same distance at equal time intervals, regardless of the duration of the time interval.
Answer:
hope it's help you
Explanation:
In Uniform motion, the movement of a body is along the straight line with constant speed. In non uniform motion, the movement of a body is along the straight line with variable speed. In uniform motion, the body covers equal distance in an equal interval of time.
Mercury is used in thermometer.Give reason
Answer:
Mercury is the only one in liquid state at room temperature
D=12000 m
T= 30min
V=?
Ayudenme en este ejercicio xfa
En m/min y en Km/h
A bike travels at 3.0 m/s, and then accelerates to a speed of
8.5 m/s in a time of 2.5 seconds. The average acceleration of
the bike is
m/s2
The average acceleration of the bike is 2.2 m/s²
What is average acceleration?Acceleration, rate at which velocity changes with time, in terms of both speed and direction.
A point or an object moving in a straight line is accelerated if it speeds up or slows down.
According to the question,
Given, initial velocity, u=3.0m/s and final velocity v=8.5 m/s
Time = 2.5 seconds
If a be the acceleration.
a = [tex]\frac{v-u}{t}[/tex]
a = [tex]\frac{8.5 - 3.0}{2.5s}[/tex]
⟹ a=2.2 m/s²
So, The average acceleration of the bike is 2.2 m/s²
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An airplane starts from rest and undergoes a uniform acceleration of 10.8 m/s^2 for 16.7 s seconds before leaving the ground. What is its displacement?
Answer:
3012.012m
Explanation:
s=it +1/2(10.8)(16.7)^2
# Astronaut fells weightlessness in a spacecraft why?
Answer:
......... ........ ... .... .... . .. .......
.....
Explanation:
........mmmmmmmmmmm
is there any machine that is 100% efficient? why?why not
Answer:
No, it's not there.
Explanation:
For a machine to be 100% efficient, it has to be with an output which is equal to its input. But machines have an out put less than an input, hence efficiency below 100%.
The direction of applied force has to be .............. to the distance in order to say work is done
Answer:
Parallel
Explanation:
The work done is defined as the force applied on an object and the displacement in the position of the object in the direction of force.
W = F s cos A
where, F is the force, s is the displacement and A is the angle between force and displacement.
When the angle between the force and the displacement is 90 degree, the work done is zero.
To get the maximum work the angle between the force and the displacement is 0 degree.
So, to get the work done by the force the angle between the force and displacement is 0 degree that means the force and displacement is parallel to each other.
Which property do the elements in each column of the representative elements series of the periodic table have in common?(1 point)
number of neutrons
number of orbitals
number of valence electrons
number of protons
The property that the elements in each column of the representative elements series of the periodic table have in common is: number of valence electrons.
An atom can be defined as the smallest unit comprising of matter that forms all chemical elements. Thus, atoms are basically the building blocks of matters and as such determines or defines the structure of a chemical element.
Generally, atoms are typically made up of three distinct particles and these are protons, neutrons and electrons.
Periodic table is an organized tabular array of all the chemical elements arranged in order of increasing atomic number (in rows).
Valence electrons can be defined as the number of electrons present in the outermost shell of an atom. Valence electrons are used to determine whether an atom or group of elements found in a periodic table can bond with others. Thus, this property is typically used to determine the chemical properties of elements.
In the periodic table, chemical elements that are having the same number of valence electrons are found in the same column.
This ultimately implies that, all the chemical elements such as Hydrogen, Sodium, etc., with one (1) valence electrons in their outermost shell (S-orbital) are found in the first (1st) column of the periodic table.
In conclusion, property that the chemical elements in each column of the representative elements series of the periodic table have in common is number of valence electrons.
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A stone is thrown into a pond. Five waves were made from the same source in 10 seconds.
The frequency of the wave for the stone thrown in the pond is 0.5Hertz.
The question does not specify what to calculate but we can look for the frequency of the wave.
Frequency is the number of oscillations completed in one second. This is interpreted as:
x oscillations = 1second
If Five waves were made from the same source in 10 seconds for a stone that is thrown inside the pond, then:
5 oscillations = 10seconds
Divide both expressions to get x (the required frequency)
x/5 =1/10
Cross multiply
10x = 5
Divide both sides by 10
10x/10 = 5/10
x = 1/2
x = 0.5Hertz
Hence the frequency of the wave is 0.5Hertz.
NB: The period of the wave is simply the reciprocal of the frequency.
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I NEED HELP ASAP!!!
What is the average speed shown on the graph between point A and point D?
Answer:
5/3 m/s or
6 km/h
Explanation:
really ? the average speed is just the straight connection in the graph from A to D.
that means the travel time was 40-10 seconds = 30 seconds.
and the distance traveled was 60-10 = 50 meters.
so, the average speed was
50 meters / 30 seconds
to bring this to standard m/s
5 m / 3 s = 5/3 m/s
or to standard km/h
an hour has 60 minutes or 120 30-seconds intervals
50 m/ 30 s × 120/120 = 6000 m / h = 6 km/h
If star A is 20 light years away from earth and star B is 40 light years away from earth,which star appears brighter and by what factor?
Answer:
Because Star A and Star B have identical luminosities, the difference in their apparent brightness is due solely to distance. Star B is twice as far from Earth as Star A.
Explanation:
(Q008) Magnetic anomalies are a. found only on the seafloor. b. measured with an instrument called an inclinometer. c. defined as the angle between which a compass needle points and the longitude at that point. d. places where the magnetic field strength is either greater or less than the expected strength.
Answer: D. places where the magnetic field strength is either greater or less than the expected strength.
Explanation:
Magnetic anomaly refers to the change in the magnitude of the magnetic field of the Eatth with respect to the location's expected value.
Magnetic anomalies are places where the magnetic field strength is either greater or less than the expected strength. Therefore, the correct option is D.
differniate between Magnetic force and electrostatic force
Answer:
magnetic force:
i) It is exerted by a magnet.
ii)Magnetic forces are always normal to the direction of the velocity of the charge it acts upon.
Electrostatic force
i) It is exerted by electrically charged body.
ii)Electric force are independent of the direction the charge moves in.
✌✌✌✌
Our Moon a. was a separate small planet before it was captured by the Earth's gravity. b. spun off the fast-spinning Earth during the early formation of the Solar System. c. coalesced from gas and dust in its current place next to the Earth. d. was formed by the collision of the Earth with a Mars-sized protoplanet.
Answer:
d. was formed by the collision of the Earth with a Mars-sized protoplanet.
According to the The giant-impact hypothesis the Moon was formed from the debris of a collision between the Earth and a Mars-sized protoplanet.
Which are characteristics of a prokaryotic cell? Select three options.
O contains DNA
O lacks DNA
O contains ribosomes
O lacks ribosomes
O contains a nucleus
O lacks a nucleus
I NEED THIS QUICKLY
Answer:
A. Contains DNA
C. Contains ribosomes
F. Lacks a nucleus
Explanation:
5. Which one of the following factors is directly proportional to density of liquid? (a) Temperature (b) Volume of liquid (c) Upthrust (d) Density of object
Answer:
A
The upthrust on a floating body is in upwards direction and is equal to the weight of the liquid displaced
B
The upthrust is directly proportional to the density of the liquid in which the solid is immersed
C
The upthrust is directly proportional to the volume of the fluid displaced by a solid
The upthrust acts on the body in upward direction at the center of buoyancy.
Upthrust is equal to the weight of liquid displaced by object and weight of liquid will depend on its density.
Upthrust is F=Vρg ,where V is the volume of liquid displaced and ρ is the density of fluid.
The total lateral pressure acting on an immersed object on one side is equal and in opposite direction to the total lateral pressure acting on the other side.
The heat required to raise 3 kg of copper from 0°C to 10°C raises 1kg of lead from 10°C to 100°C. If the specific heat capacity of copper is 0.095 cal/g°C,find the specific heat capacity of lead.
The specific heat capacity of lead has been determined to be 0.032 cal/g°C.
The specific heat capacity of a substance is the amount of heat required to increase the temperature of its unit mass by 1 Kelvin rise in temperature. There is no phase change during the process. This can be expressed as:
Q = mcT
c = [tex]\frac{Q}{mT}[/tex]
Where c is the specific heat capacity of the substance, Q is the quantity of heat required, m is the mass of the substance and T is its change in temperature.
In the given question, the heat emitted by the copper mass would be absorbed by the lead mass.
So that;
heat emitted by copper = heat absorbed by lead
[tex]m_{c}[/tex] [tex]c_{c}[/tex]([tex]T_{2}[/tex] - [tex]T_{1}[/tex]) = [tex]m_{l}[/tex][tex]c_{l}[/tex]([tex]T_{2}[/tex] - [tex]T_{1}[/tex])
With the given information in the question, the above equation is expressed as:
3 * 0.095 * (10 - 0) = 1 * [tex]c_{l}[/tex]* (100 - 10)
3*0.095*10 = [tex]c_{l}[/tex] * 90
2.85 = [tex]c_{l}[/tex]*90
[tex]c_{l}[/tex] = [tex]\frac{2.85}{90}[/tex]
= 0.031667
[tex]c_{l}[/tex] = 0.032 cal/g°C
Therefore, the specific heat capacity of lead is 0.032 cal/g°C.
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state the term used to describe the turning force exerted by the man pushing down on a lever to lift one end of a heavy log
The term used to describe the turning force exerted when pushing an object is effort.
What is effort?The is the input force or force applied at one point of a lever in order to overcome a load.
The relationship between effort, load and mechanical advantage of a lever is given as;
M.A = L/E
where;
M.A is mechanical advantageL is the loadE is the applied force or effortThus, the term used to describe the turning force exerted when pushing an object is effort.
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valancy of an atom is +2. what does it mean.
Answer: I hope you find it useful
Explanation: Group 2 elements have two valence electrons. The two valence electrons are easily lost in the formation of chemical bonds. Once the two electrons are lost, the atom then has a full outer shell and is therefore more stable.
so, if an atom has valency 2 , then it means that the atom can combine with 2 other atoms .
6. 15. A boy takes 5 seconds to reach each point from ‘A’ to ‘B’, ‘B’ to ‘C’ and ‘C’ to ‘D’ as
shown in the diagram. If AB = BC = CD = 20 m then which of the following information is
correct when the boy reaches point D from point A via BC?
Explanation:
Could you also show the diagram
What is the relation between the weight of a body and acceleraton due to gravity?
Answer:
All objects on Earth, regardless of their mass, accelerate due to gravity at the same rate - that is, 9.8 m/sec2. The weight of an object can be calculated using the formula for force - F = m * a - where F equals the weight of the object and now the acceleration (a) is the acceleration of gravity (g).
