Answer:
(b) Friction increases as the normal force (weight) increases, and also depends on the surface
Explanation:
The coefficient of friction relates the normal force between surfaces to the friction force opposing motion. The coefficient depends on the surface.
The appropriate choice is ...
Friction increases as the normal force (weight) increases, and also depends on the surface
9. In Millikan's oil drop experiment an oil
drop is held stationary by p.d) of 400 V,
if another drop of double the radius bu
carries same charge is to be held
stationary, the p.d) required is
a) 800 V
b) 1600 V
c) 3200 V
d) 400 V
The strona
The angle between incident ray and reflected ray is 60°. What will be the value of angle of incidence and angle of reflection.?
The angle between incident ray and reflected ray is 60 degree. the value of angle of incidence and angle of reflection is 30 degree
1. A book resting on a shelf was found
to have a gravitational potential energy
of 12 J relative to the ground. If the
book falls to the ground, neglecting air
resistance, what is the kinetic energy of
the book just as it was about to hit the
ground?
Answer:
12J
Explanation:
Right before it hits the ground, the initial potential energy and the final kinetic energy will equal each other due to conservation of energy.
A 50.0-kg child stands at the rim of a merry-go-round of radius 2.00 m, rotating in such a way that it makes one revolution in 2.09 s. What minimum coefficient of static friction between her feet and the floor of the merry-go-round is required to keep her in the circular path
Answer:
2.01
Explanation:
First, we need to find the centripetal acceleration.
We're given that the merry go round rotates 1 revolution in 2.09 seconds. Converting to rpm, we know that it rotates 30 revolution per minute
Now this speed gotten in rpm will be converted to m/s, to ease the calculation
30 rpm = πdN/60 m/s
30 rpm = (3.142 * 4 * 30)/60
30 rpm = 377.04/60
30 rpm = 6.284 m/s
a(c) = v²/r
a(c) = 6.284²/2
a(c) = 39.49 / 2
a(c) = 19.74 m/s²
F = ma
F = 50 * 19.74
F = 987 N
Also, Normal Force, F(n) =
F(n) = mg
F(n) = 50 * 9.81
F(n) = 490.5
We then use this to find the coefficient of static friction, μ
μ = F/F(n)
μ = 987 / 490.5
μ = 2.01
please help!!!
In an electric motor, how do the permanent magnets and the electromagnet
interact?
PLEASE ANSWER FAST
A. The electromagnet causes the permanent magnets to reverse
poles.
B. The permanent magnets reverse the current in the electromagnet.
C. The electromagnet reverses the current in the permanent
magnets.
D. The permanent magnets cause the metal loop in the
electromagnet to turn.
if you don’t know don’t answer
The correct asnwer is D. The permanent magnets cause the metal loop in the
electromagnet to turn.
In an electric motor, the permanent magnets cause the metal loop in the
electromagnet to turn. So, option (D) is correct.
What is electric motor?An electrical device that transforms electrical energy into mechanical energy is an electric motor. The majority of electric motors work by creating force in the form of torque imparted to the motor shaft through the interplay of the magnetic field of the motor and electric current in a wire winding.
In an electric motor, their remains a permanent magnet to produce constant magnetic field. When electric current is passed through the conducting loop, it acts ling electromagnet and begins to rotate. Thus an electric motor works. Hence, option(D) is correct.
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10. During 4th period we put Klaudia in a box because she was talking too much. We still heard her voice through the box so we decided to push her outside. The force of friction of the ground on the box was 68 N. If Mr.Whitmore can apply a force of 25 N and every other 7th grade student can apply a force of 6 N. How many students would Mr. Whitmore need to make the box start moving and go outside. (Think quickly, the faster we move the box out, the quicker she stops talking)
Answer: Mr. Whitmore would need 7 or more students ( 7.17) to make the box start moving and go outside
Explanation:
Given that;
friction force of ground box = 68 N
student of 7th grade = n
Whitmore can apply a force of 25 N
every other 7th grade student can apply a force of 6 N.
now
friction force = forced applied by whitmore + total force ny 7th grade student
we substitute
68 = 25 + 6n
6n = 68 - 25
6n = 43
n = 43/6
n = 7.17
Therefore Mr. Whitmore would need 7 or more students ( 7.17) to make the box start moving and go outside
difference between incident ray and refracted ray
Answer:
** incident ray.
Incident ray - the ray of light falling on the surface AB is called the incident ray
reflected ray.
** Reflected ray - the incident ray bouncing back in the same medium after striking the reflecting surface is called reflected ray.
a guitar string is 0.620 m long, and oscillates at 234 Hz. if a player uses his finger to shorten the string to 0.480 m, what is the new frequency?
Answer:
the new frequency is : 302.25Hz
using the formula F2 = [tex]\frac{F1 L1}{L2}[/tex]
Explanation:
meaning of frequencyfrequency of a string is the number of vibrations of a plucked string per second. it is measured in Hertz.
the frequency of a string is inversely proportional to twice the length of the string. which means the longer the string, the smaller the freqency and the higher the string the higher the frequency.
f ∝ 1/2L.
f = k/2L
where f = frequency
L = length of string
k = constant
k = 2fL is a constant
given data
L1 = 0.62m
f1 = 234Hz
L2 = 0.48m
2f1L1 = 2f2L2
f1L1 = f2L2
f2 = f1L1/L2
f2 = [tex]\frac{234 x 0.62}{0.48}[/tex] = 302.25Hz
in conclusion, the new frequency is 302.25Hz
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A car accelerates at 2 m/s2. Assuming the car starts from rest, how much time does it need to accelerate to a speed of 16 m/s?
Answer:
8 seconds
Explanation:
as per 1st equation of motion
v=u+at,
u= initial velocity, v= final velocity , t=time, a=acceleration
since it starts from rest , u=0
v=16m/s
a=2m/s^2
16=0+2t
16=2t
t=8
An earth satellite travels in a circular orbit at 20,000 mph if the radius of the orbit is 4,300 mi what angular velocity is generated?
Answer:
0.00129rad/s
Explanation:
The angular velocity is expressed as;
v = wr
w is the angular velocity
r is the radius
Given
v = 20,000 mph
r = 4300mi
Get w;
w = v/r
w = 20000* 0.44704/4300*1609.34
w = 8940.8/6,920,162
w = 0.00129rad/s
Hence the angular velocity generated is 0.00129rad/s
The signal from the oscillating electrode is fed into an amplifier, which reports the measured voltage as an rms value, 1.0 nV . What is the potential difference between the two extremes
Answer:
The value is [tex]V = 2.8284 *10^{-9 } \ Volts[/tex]
Explanation:
From the question we are told that
The measure voltage is [tex]E_{rms} = 1.0 \ n V = 1.0 *10^{-9} \ V[/tex]
Generally the peak voltage is mathematically represented as
[tex]E_{max} = \sqrt{2} * E_{rms}[/tex]
=> [tex]E_{max} = \sqrt{2} * 1.0 *10^{-9}[/tex]
=> [tex]E_{max} = 1.4142 *10^{-9} \ volts[/tex]
Generally the potential difference between the two extremes is mathematically represented as
[tex]V = 2 * E_{max}[/tex]
=> [tex]V = 2 * 1.4142 *10^{-9}[/tex]
=> [tex]V = 2.8284 *10^{-9 } \ Volts[/tex]
A motorcyclist increases the velocity of his bike from 30.0 meters/second to 55.0 meter/second under a constant acceleration of 5.00 meters/second^2. How long does it take the bike to reach the final velocity?
Answer:
Time, t = 5 seconds.
Explanation:
Given the following data;
Initial velocity = 30m/s
Final velocity = 55m/s
Acceleration = 5m/s²
To find the time, we would use the first equation of motion;
[tex] V = U + at[/tex]
Where;
V is the final velocity. U is the initial velocity. a is the acceleration. t is the time measured in seconds.Making time, t the subject of formula, we have;
[tex] t = \frac{V - U}{a}[/tex]
Substituting into the equation, we have;
[tex] t = \frac{55-30}{5}[/tex]
[tex] t = \frac{25}{5}[/tex]
Time, t = 5 seconds.
Therefore, it would take the bike 5 seconds to reach the final velocity.
Is anyone good at science I need help with 2 tests
Answer:
i am!
Explanation:
define paralax error pls
Answer:
Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines.
Why do you need air resistance in a parachute ?what happens without it?
And
How does air resistance affect acceleration and terminal velocity
You have to choose one of these Kpop members for the purge, or you can group them into three. Who do you choose, what are their skills, why are they one of the best choices?
- Namjoon
- Wonho
- Felix
- Seonghwa
- Bangchan
- Zico
Answer:
Wonho, Seonghwa, and Bangchan
Explanation:
Answer:
namjoon,seonghwa,bangchan
Explanation:
How can you measure the strength of any electric field?
Answer:
The strength of the source charge's electric field could be measured by any other charge placed somewhere in its surroundings. The charge that is used to measure the electric field strength is referred to as a test charge since it is used to test the field strength. The test charge has a quantity of charge denoted by the symbol q.
Explanation:
Electric field strength is a vector quantity; it has both magnitude and direction. The magnitude of the electric field strength is defined in terms of how it is measured. Let's suppose that an electric charge can be denoted by the symbol Q. This electric charge creates an electric field; since Q is the source of the electric field, we will refer to it as the source charge. The strength of the source charge's electric field could be measured by any other charge placed somewhere in its surroundings. The charge that is used to measure the electric field strength is referred to as a test charge since it is used to test the field strength. The test charge has a quantity of charge denoted by the symbol q. When placed within the electric field, the test charge will experience an electric force - either attractive or repulsive. As is usually the case, this force will be denoted by the symbol F. The magnitude of the electric field is simply defined as the force per charge on the test charge.
A homeowner wants some insulation blown into her attic. The original quote was for 16 cm of R-17 rated insulation. If she wants the attic insulated to R-44, what thickness (in cm) does she need to use
Answer: the value of the required thickness is 41.4 cm
Explanation:
Given that;
R1 = 17
R2 = 44
L1 = 16
L2 = ?
we know that, from thermal conductivity formula
P = 1 / R
P = k / L
1 / R = k / L
since k of a distinct material is constant,
we can take
L / R = constant
L1 / R1 = L2 / R2
L1R2 = L2R1
L2 = (L1 × R2) / R1
so we substitute
L2 = (16 × 44) / 17
L2 = 704 / 17
L2 = 41.4 cm
Therefore the value of the required thickness is 41.4 cm
Drag each item to indicate whether it is a characteristic of dark matter or baryonic matter. (2 points)
Dark Matter
Baryonic Matter
:: has been observed directly
:: interacts with baryonic matter
:: interacts with electromagnetic radiation
has not been observed directly
:: does not interact with electromagnetic radiation
++ does not interact with baryonic matter
Answer:
Dark matter:
- Doesn't interact with baryonic matter.
- It has not been observed directly
- dark matter does not absorb, reflect or even emit light, thereby making it to be extremely hard to spot. Therefore, it does not interact with electromagnetic radiation.
Explanation:
Dark matter:
- Doesn't interact with baryonic matter.
- It has not been observed directly
- dark matter does not absorb, reflect or even emit light, thereby making it to be extremely hard to spot. Therefore, it does not interact with electromagnetic radiation.
Baryonic matter:
- Has been observed directly because it includes nearly all the matter that we see in the world daily.
- It interacts with baryonic matter
- interacts with electromagnetic radiation
Dark Matter:
It has not been observed directly.It does not interact with baryonic matter.It does not interact with electromagnetic radiation.Baryonic Matter:
It has been observed directly.It interacts with baryonic matter.It interacts with electromagnetic radiation.Dark matter can be defined as often invisible substances that are difficult to spot because they don't absorb, emit or reflect light.
Hence, dark matter do not affect human view because they do not interact or interfere with electromagnetic radiation (force).
Although, humans can see right through the (weakly interacting) dark matter but it has not been observed directly.
Baryonic matter can be defined as a dark matter that is made up of baryons such as neutrons, and protons. Also, they are ordinary matter (both fermions and hadrons), as distinct from exotic forms.
In conclusion. baryonic matter has been observed directly and it can interact with electromagnetic radiation.
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Explain the difference between a high tide and a low tide.
Answer: Tidal range
Explanation:
Tides are considering the rise and fall of sea levels and there are two types of it which are called high tide and low tide. The difference between high tide and low tide is called the tidal range.
The tidal range is not constant and it is considering height difference. It can change and it is depending on the locations of the Sun or the Moon.
High tide is the highest level of the place where the water rises because when the water rises to its highest level, then the water is reaching its high tide.When it comes to low tide, then it is the opposite of high tide. Water is reaching its lowest level.
Two balls with masses of 2.0 kg and 6.0 kg travel toward each other at speeds of 12 m/s and 4.0 m/s, respectively. If the balls have a head-on, inelastic collision and the 2.0-kg ball recoils with a speed of 8.0 m/s, how much kinetic energy is lost in the collision
Answer:
The kinetic energy lost in the collision is 48 J
Explanation:
Given;
mass of the first ball, m₁ = 2.0 kg
mass of the second ball, m₂ = 6.0 kg
initial speed of the first ball, u₁ = 12 m/s
initial speed of the second ball, u₂ = 4 m/s
let v be the final velocity of the two balls after the inelastic collision
Apply the principle of conservation of linear momentum;
m₁u₁ + m₂u₂ = v(m₁ + m₂)
2 x 12 + 6 x 4 = v(2 + 6)
48 = 8v
48 / 8 = v
v = 6 m/s
The initial kinetic energy of the balls is calculated as;
K.E₁ = ¹/₂m₁u₁² + ¹/₂m₂u₂²
K.E₁ = ¹/₂(2)(12²) + ¹/₂(6)(4)²
K.E₁ = 144 + 48
K.E₁ = 192 J
The final kinetic of the balls is calculated as;
K.E₂ = ¹/₂(m₁ + m₂)(v²)
K.E₂ = ¹/₂(2 + 6)(6²)
K.E₂ = ¹/₂(8)(6²)
K.E₂ = 144 J
The lost in kinetic energy of the balls is K.E₂ - K.E₁ = 144 J - 192 J = -48 J
Therefore, the kinetic energy lost in the collision is 48 J
how do i find out the maximum speed and things? also, if you can give the answer and tell me why that would be amazing!!
Answer:
See the answers and the explanation below.
Explanation:
To solve these questions we must understand that speed is the relationship between the displacement and the time that the displacement lasts.
1. 300 [km], in 5 [hr]
d = displacement [km]
[tex]v = d/t[/tex]
where:
v = velocity [km/h]
t = time [hr]
[tex]v = 300/5\\v = 60 [km/h][/tex]
In one hour : [tex]d = 60*1\\d = 60 [km][/tex]
b. Car B 100 [km] in 2 [hr]
[tex]v =100/2\\v = 50 [km/h]\\[/tex]
C. The car A has the greatest average speed.
Why might scientists use a model to show the movement of the continents?
A. The actual movement is too fast.
B. The actual movement is too complex.
C. The actual movement is too dangerous.
D. The actual movement is too slow.
I
HELPPP!!
Answer:
too slow
Explanation:
so its d
To solve this we must be knowing each and every concept related to continent. Therefore, the correct option is option D among all the given options.
What is continent?A huge landmass that is distinguished from other landmasses by seas is referred to be a continent. Seven continents make up the Earth's land mass. Some are connected and split merely by an arbitrary line, while others, like a large island, are completely encircled by sea.
Millions of years is required for the formation of a continent. The lithosphere's separate plates move apart from one another at a pace of three to twenty centimeters (1 to 8 inches) every year. Scientists might use a model to show the movement of the continents as the actual movement is too slow.
Therefore, the correct option is option D among all the given options.
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A pinball machine launches a .045 kg ball at a speed of 9.2 m/s. Determine the potential energy of the spring just before it launched the pinball
Given :
A pinball machine launches a .045 kg ball at a speed of 9.2 m/s.
To Find :
The potential energy of the spring just before it launched the pinball.
Solution :
We know, their is no external force applied on system.
It means that kinetic energy will remains constant.
Initial Energy = Final Energy
[tex]K.E_i + P.E_i = K.E_f + P.E_f\\\\0 + P.E_i= \dfrac{mv^2}{2}+ 0\\\\P.E_i = \dfrac{0.045 \times 9.2^2}{2}\ J\\\\P.E_i = 1.9044\ J[/tex]
Therefore, the potential energy of the spring just before it launched the pinball os 1.9044 J.
A mechanic uses a lift to raise an 11,760 N car 0.50m off the ground. How much work does the lift do on the car?
Answer:
5880 JExplanation:
The work done by an object can be found by using the formula
workdone = force × distance
From the question we have
workdone = 11760 × 0.5
We have the final answer as
5880 JHope this helps you
Follow these steps:
A. Place some hot water in the bottom of the bottle and put the ice cube over the opening of the
bottle so that it rests on top and drips into the bottle.
B. Observe carefully what happens over the next 15 minutes. Make a sketch of your experiment
and write down your observations.
Explain your observations using the terms:
condensation
evaporation
solid
Answer:
is this for a project im a little confused
Answer:
Some of the hot water evaporated and became a gas called water vapor and created condensation on the sides of the bottle. It rose to the top of the solid ice cube and the cold cooled the gas turning it back into a liquid.
Explanation:
A nuclear power plant is being built to generate electricity for a large
metropolitan area. Which process will it use?
O A. Nuclear decay of uranium-238
B. Chemical decay of wood
C. Nuclear fission of uranium-235
O D. Combustion of fossil fuels
Answer:
C. Nuclear fission of uranium-235
Answer:
C. Nuclear fission of uranium-235
Explanation:
Give thanks to above me
Two men, Joel and Jerry, push against a car that has stalled, trying unsuccessfully to get it moving. Jerry stops after 10 min, while Joel is able to push for 5.0 min longer. Compare the work they do on the car.
a. Joel does 75% more work than Jerry.
b. Joel does 25% more work than Jerry.
c. Jerry does 50% more work than Joel.
d. Joel does 50% more work than Jerry
e. None of the above .
Answer:
the answer is B
Explanation:
draw simple vector diagram and resolve 60N at an angle of 30° from the horizontal.. plz help guys
Explanation:
The attatched figure shows the vector diagram for a force that has magnitude of 60 N and it is acting at an angle of 30° from the horizontal.
When it is resolved, the horizontal and vertical components are given by :
[tex]F_x=F\cos\theta\\\\=60\times \cos30\\\\=51.96\ N[/tex]
And
[tex]F_y=F\sin\theta\\\\=60\times \sin30\\\\=30\ N[/tex]
Hence, this is the required solution.
At a state championship High School football game, the intensity level of the shout of a single person in the stands at the center of the field is 48.1 dB. What would be the intensity level at the center of the field if all 4841 fans at the game shouted from roughly the same distance away from that center point
Answer:
The value is [tex]\beta_f = 84.95 \ dB[/tex]
Explanation:
From the question we are told that
The intensity level of the shout of a single person is [tex]\beta = 48.1 \ dB[/tex]
The number of fans is [tex]n = 4841[/tex]
Gnerally intensity level is mathematically represented as
[tex]\beta = 10 log * \frac{I}{I_o }[/tex]
Here [tex]I_o[/tex] is the minimum intensity of sound human ear can pick and the value is
[tex]I_o = 1 * 10^{-12} \ W/m ^2[/tex]
when [tex]\beta = 48.1 \ dB[/tex]
[tex]48.1 = 10 log * \frac{I}{ 1 * 10^{-12}}[/tex]
=> [tex]4.81 = log ( \frac{ I}{ 1 * 10^{-12}} )[/tex]
taking antilog of both sides
[tex]64565.42 = \frac{I}{ 1 *10^{-12}}[/tex]
=> [tex]I = 6.457 *10^{-8} \ W/m^2[/tex]
Generally the intensity for the whole fans is mathematically represented as
[tex]I_f = n * I[/tex]
=> [tex]I_f = 4841 * 6.457 *10^{-8 }[/tex]
=> [tex]I_f = 0.0003126 \ W/m^2[/tex]
Gnerally the intensity level for the whole fans is mathematically represented as
[tex]\beta_f = 10 log [ \frac{I_f }{I_o } ][/tex]
=> [tex]\beta_f = 10 log [ \frac{ 0.0003126 }{1*10^{-12}}[/tex]
=> [tex]\beta_f = 84.95 \ dB[/tex]