Answers
The car's forward motion is opposed by the friction between the road and the tires and by the resistance of the air.
Kinesha and her friend were watching a solar eclipse. Kinesha explains to her friend that a solar eclipse means that Earth is located between the Sun and the Moon. Her friend tells Kinesha that her explanation is incorrect. Why?
this is where the sun and moon line up where you asleep only a tiny bit of the sun it's pretty cool to see
Explanation:
a solar eclipse means when the moon goes infront of the sun and the earth turns dark
If a = 8i + j - 2k and b = 5i - 3j + k show that a) a x b = -5i - 18j - 29k b) b X a = 50 + 18j +29k
Recall the definition of the cross product with respect to the unit vectors:
i × i = j × j = k × k = 0
i × j = k
j × k = i
k × i = j
and that the product is anticommutative, so that for any two vectors u and v, we have u × v = - (v × u). (This essentially takes care of part (b).)
Now, given a = 8i + j - 2k and b = 5i - 3j + k, we have
a × b = (8i + j - 2k) × (5i - 3j + k)
a × b = 40 (i × i) + 5 (j × i) - 10 (k × i)
… … … … - 24 (i × j) - 3 (j × j) + 6 (k × j)
… … … … + 8 (i × k) + (j × k) - 2 (k × k)
a × b = - 5 (i × j) - 10 (k × i) - 24 (i × j) - 6 (j × k) - 8 (k × i) + (j × k)
a × b = - 5k - 10j - 24k - 6i - 8j + i
a × b = -5i - 18j - 29k
Answer:
Explanation:
If a = 8i + j - 2k and b = 5i - 3j + k show that a) a x b = -5i - 18j - 29k b) b X a = 50 + 18j +29k
Consider 5.00 mol of liquid water. (a) What volume is occupied by this amount of water? The molar mass of water is 18.0 g/mol. (b) Imagine the molecules to be, on average, uniformly spaced, with each molecule at the center of a sma11 cube. What is the length of an edge of each sma11 cube if adjacent cubes touch but don't overlap? (c) How does this distance compare with the diameter of a molecule?
This question involves the concepts of density, volume, and mass.
(a) The volume occupied by this amount of water is "90 m³".
(b) The length of an edge of each small cube is "83 μm".
(c) The length of the edge of each small cube is "equal" to the diameter of a molecule.
(a)
The volume can be found using the following formula:
[tex]V = \frac{nM}{\rho}[/tex]
where,
V = volume occoupied = ?
n = no. of moles = 5 mol
M = molar mass = 18 g/mol
[tex]\rho[/tex] = density of water = 1 g/m³
Therefore,
[tex]V=\frac{(5\ mol)(18\ g/mol)}{1\ g/m^3}\\\\[/tex]
V = 90 m³
(b)
First, we will find the volume of an individual molecule:
[tex]V_i =\frac{V}{nN_A}[/tex]
where,
[tex]N_A[/tex] = Avogadro's number = 6.02 x 10²³ molecules/mol
Therefore,
[tex]V_i=\frac{90\ m^3}{5\ mol(6.02\ x\ 10^{23}\ molecules/mol)}[/tex]
Vi = 3 x 10⁻²³ m³
This volume can be given as a volume of the sphere:
[tex]V_i=\frac{4}{3}\pi r^3\\\\r=\sqrt[3]{\frac{3(3\ x\ 10^{-23}\ m^3)}{4\pi}}[/tex]
r = 4.15 x 10⁻⁷ m
Diameter = d = 2r = 2(4.15 x 10⁻⁷ m)
d = 8.3 x 10⁻⁷ m = 83 μm
since the cubes are adjacent to each other. Therefore, the diameter will be equal to the edge length.
Edge Length = L = d
L = 8.3 x 10⁻⁷ m = 83 μm
(c)
The edge length is equal to the diameter of the molecule.
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Light bulbs produce useful energy in the form of light and waste energy in the form of heat. What kind of light bulb would you use
to incubate eggs?
A. low-efficiency light bulbs, because they produce more light
B. low-efficiency light bulbs, because they produce more heat
C. high-efficiency light bulbs, because they produce more heat
D. high-efficiency light bulbs, because they produce more light
Answer:
C) high efficiency light bulbs, because they produce more heat
Light bulbs produce useful energy in the form of light and waste energy in the form of heat, the kind of light bulb would you use to incubate eggs are low-efficiency light bulbs, because they produce more heat, therefore the correct answer is option B.
What is thermal energy?It can be defined as the form of the energy in which heat is transferred from one body to another body due to their molecular movements, thermal energy is also known as heat energy.
The type of light bulb you would use to incubate eggs is a low-efficiency light bulb since they produce more heat; consequently, option B is the right response. Light bulbs produce useful energy in the form of light and waste energy in the form of heat.
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(a) What frequency is received by a person watching an oncoming ambulance moving at 105 km/h and emitting a steady 853 Hz sound from its siren
Answer:
(a) f' = 878 Hz
(b) f' = 735 Hz
Explanation:
Pls help, I really need it and plz show steps I will give brainliest..
Answer:
21.31 meters
Explanation:
Since we're working with gravitational potential energy (GPE):
GPE (Joules) = mass (kg) * gravity (m/s^2) * height (meters)
1. Figure out what we have:
GPE = mass * gravity * height
We're looking for height, and we have the other three, so we're set to move on.
2. Isolate the unknown variable (height):
(GPE) / (mass * gravity) = height
3. Plug in your numbers:
(3.78 * 10^7 J) / ((1.81 * 10^5 kg) * (9.8 m/s^2)) = 21.31 meters
PLEASE HELP IF YOU CAN
Is the acceleration change or constnt?
1. It’s fall and time for the corn maze and bonfire and you just can’t wait. On your way to the farm though a turkey flies out in front of you, so you slam on the brakes and go from from 30.0 m/s to 18.0 m/s. Luckily your date brought a stop watch and told you the whole thing took place in 10.5s. What is your acceleration and how far did you go?
Acceleration = (change in velocity ( final speed - starting speed))/ (time)
Acceleration = (18-30)/10.5
Acceleration = -12/10.5
Acceleration = -1.14 m/s^2
Distance = 30m/s x 10.5s + 1/2(1.14)(10.5)^2
Distance = 252.2 meters
Four year old Sam has been hitting other children at preschool. He may have learned this behavior from his parents who regularly spank him. What approach to personality best explains Sam's behavior?
A. psychodynamic
B. behavioral
C. humanistic
D. biological
A. psychodynamic is the personality best explains Sam's behavior
What is psychodynamic ?
The psychology of mental or emotional forces or processes developing especially in early childhood and their effects on behavior and mental states is called psychodynamic .
Since , any behavior is not genetical or it never get inherited hence it is not biological . This has been grown with time and this behavior have been grown in Sam by observing his parents doing the same hence correct option should be A. psychodynamic
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What is the angle θ between vectors A⃗ and B⃗ if A⃗ =4ı^−4ȷ^ and B⃗ =−5ı^+7ȷ^?
The characteristics of the scalar product allows to find the angle between the two vectors is:
The angle θ = 170º
The scalar product is the product between two vectors whose result is a scalar.
A . B = |A| |B| cos θ
Where A and B are the vectors, |A| and |B| are the modules of the vectors and θ at the angle between them.
The vector is given in Cartesian coordinates and the unit vectors in these coordinates are perpendicular.
i.i = j.j = 1
i.j = 0
A . B = (4 i - 4j). * -5 i + 7j)
A . B = - 4 5 - 4 7
A. B = -48
We look for the modulus of each vector.
|A| = [tex]\sqrt{x^2 +y^2 }[/tex]
|A| = [tex]\sqrt{4^2 + 4^2}[/tex]
|A| = 4 √2
|B| = [tex]\sqrt{5^2 +7^2}[/tex]
|B| = 8.60
We substitute.
-48 = 4√2 8.60 cos θ
-48 = 48.66 cos θ
θ = cos⁻¹ [tex]\frac{-48}{48.664}[/tex]
θ = 170º
In conclusion using the dot product we can find the angle between the two vectors is:
the angle θ = 170º
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Một khối khí hidro bị nén đến thể tích bằng 1/2 lúc đầu khi nhiệt độ không đổi. Nếu vận tốc trung bình của phân tử hidro lúc đầu là V thì vận tốc trung bình sau khi nén là bao nhiêu ?
answer: what language is this???
Pls help me with this one :))
Answer:
Row A is correct
Explanation:
both conduction and convection require mass to complete any heat transfer. A vacuum contains no mass
1- A soccer ball was kicked from the ground with an initial speed of 12m/s at an
angle 32° above the horizontal. What are the x and y positions of the ball
0.50s after it is kicked?
Answer:
Y = 0.5 × 6.36 m/s = 3.18 meters
X = 0.5 × 10.18 m/s = 5.09 meters
Explanation:
X and Y components:
Y = 6.36 m/s
X = 10.18 m/s
Position after 0.5 seconds:
Y = 0.5 × 6.36 m/s = 3.18 meters
X = 0.5 × 10.18 m/s = 5.09 meters
The x and y positions of the ball 0.50s after it is kicked are 5.09 meter and 1.95 meter respectively.
What is velocity?
The rate at which a body's displacement changes in relation to time is known as its velocity. Velocity is a vector quantity with both magnitude and direction. SI unit of velocity is meter/second.
Given parameters:
Initial speed of the soccer ball at an angle 32° above the horizontal is: u = 12m/s.
Time interval: t = 0.50 second.
Now, x component of initial velocity = u cosθ = 12 × cos 32° m/s = 10.17 m/s.
y component of initial velocity = u sinθ = 12 × sin32° =6.36 m/s.
Hence,
after 0.50 s, x-position of the ball = u cosθ t
= 10.17 × 0.50 meter
= 5.09 meter.
after 0.50 s, y-position of the ball = u sinθ t -gt²/2
= 6.36 × 0.50 - (9.8×0.50²/2) meter
= 1.95 meter.
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please answer fast in hindi
Answer:
1. Dheere Dheere (slowly slowly)
2. Har (every)
3. Kal (tomorrow)
4. Mat (don't)
5. Andar (inside)
sorry I wasn't able to write in hindi
what is the specific latent heat of fusion of water?
Answer:
334
Explanation:
A Vector that starts from
Origin is called what?
Work is required to lift a barbell. How many times more work is required to lift the barbell 2 times as high?
Answer:
2 times more work
Explanation:
Work is a force times distance
W = Fd
The barbell does not change mass so its weight (force) is constant.
That means work is directly proportional to the distance traveled.
twice the distance means twice the work.
In a model generator, a 310-turn rectangular coil 0.075 m by 0.18 m rotates with an angular frequency of 12.2 rad/s in a uniform magnetic field of 0.64 T. What is the maximum emf induced in the coil
This question involves the concepts of the induced emf, magnetic field, and angular frequency.
The maximum emf induced in the coil is "32.68 volts".
The following formula can be used to find out the induced emf in the coil.
[tex]E =N\omega AB\ Sin(\omega t)[/tex]
But, for maximum induced emf sin function should have a value of 1. Therefore,
[tex]E = N\omega AB[/tex]
where,
E = induced emf = ?
N = No. of turns in the coil = 310 turns
ω = angular frequency = 12.2 rad/s
A = Area of coil = (0.075 m)(0.18 m) = 0.0135 m²
B = magnetic field = 0.64 T
Therefore,
[tex]E=(310)(12.2\ rad/s)(0.0135\ m^2)(0.64\ T)[/tex]
E = 32.68 volts
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2- Calculate the momentum of cruise liner of mass 20 000 tones when it is travelling at 6.0ms-1
(1 tonne = 1000kg). Note: tonne
Answer:
P = 120,000,000
Explanation:
P = m.v
m = (20,000.1000)= 20,000,000kg
v = 0.6 m/s
p = (20,000,000)(0.6)
p = 120,000,000 kg⋅m/s
Two identical vertical springs S1 and S2 have masses m1 = 400 g and m2 = 800 g attached to them. If m1 causes spring S1 to stretch by 4 cm, what is the ratio of the potential energy of S1 and S2? Use g = 10 m/s^2
Select one:
a. 1:2
b. 4:1
c. 1:4
d. 1:3
e. 2:1
Answer:
potential energy = mgh
= 400÷1000 × 10× 4÷100
= 0.4 × 10 × 0.04
=4/10 ×10×4/100
= 4/10 × 4/10
=16/100
= 0.16 joules
m1 (400) stretches 4cm
m1 (100g) stretches 1cm
so, m2(800g) stretches 8 cm
potential energy of m2 = mgh
= 800/1000 ×10×8/100
= 0.8 × 0.8
=8/10 ×8/10
= 64/100
=0.64 joules
Ratio of s1 to s2
16/100 ÷ 64/100
= 1:4 ( answer)
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When same vectors are in the same direction they add. When same vectors are in opposite directions, they
a, also add
b, subtract
c, multiply
d, divide
Answer:
The answer is a (also add)
How much force is required to raise a 0.2 kg mass?
Answer:
1.96 N
Explanation:
⇒This is your full answer
trình bày những hiểu biết cơ bản về năng lượng
Answer:
I don't understand your language
A car C moving with a speed of 65 km/h on a straight road is ahead of motorcycle M moving with the speed of 80 km/h in the same direction. What is the velocity of M relative to A?
Answer:
The answer is 15. Step by step is you times 80 by 65 and then you divided by 2 and you call your teacher
A camera takes a properly exposed photo at f/5.6 and 1/250 s. What shutter speed should be used if the lens is changed to f/4.0?
a.1/65 s
b.1/125 s
c.1/250 s
d.1/500 s
e.1/1000 s
The shutter speed that should be used if the lens is changed to f/4.0 is; Choice D: 1/500 s.
The relationship between the shutter speed and the focal ratio is an inverse relationship.
Ratio of Areas = 5.6²/4²
A1/A2 = 1.96 = 2Since; T1A1 = T2A2
T2 = T1(A1/A2)T2 = 250 × 2 = 500 secondsIn essence; when the focal ratio is reduced as in this case; from f/5.6 to f/4.0; the shutter speed is increased.
Ultimately, the shutter speed of the camera in discuss increases to; 1/500 s.
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You are traveling along a freeway at 65 mi/h. You suddenly skid to a stop because of congestion in traffic. Where is the energy that your car once had as kinetic energy before you stopped
The work and energy theorem allows finding the result for where the kinetic energy of the car is before stopping is:
The energy becomes:
An important part in work on discs. A part in non-conservative work due to friction.
Work is defined by the scalar product of force and displacement.
W = F . d
Where the bold indicate vectors, W is work, F is force and d is displacement.
The work energy theorem relates work and kinetic energy.
W = ΔK = [tex]K_f - K_o[/tex]
In this case the vehicle stops therefore its final kinetic energy is zero, consequently the work is:
W = - K₀
Therefore, the initial kinetic energy that the car has is converted into work in its brakes. In reality, if assuming that there is friction, an important part is transformed into non-conservative work of the friction force, this work can be seen in a significant increase in the temperature of the discs on which the work is carried out.
In conclusion, using the work-energy theorem we can find the result for where the kinetic energy of the car is before stopping is:
The energy becomes:
An important part in work on the discs. A part in non-conservative work due to friction.
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A pumpkin is launched in the air and travels at a horizontal velocity of 25 meters per second for 5 seconds. How far does it travel horizontally?
Answer:
30.3 meters, 172 degrees
Explanation:
To insure the most accurate solution, this problem is best solved using a calculator and trigonometric principles. The first step is to determine the sum of all the horizontal (east-west) displacements and the sum of all the vertical (north-south) displacements.
Horizontal: 2.0 meters, West + 31.0 meters, West + 3.0 meters, East = 30.0 meters, West
Vertical: 12.0 meters, North + 8.0 meters, South = 4.0 meters, North
The series of five displacements is equivalent to two displacements of 30 meters, West and 4 meters, North. The resultant of these two displacements can be found using the Pythagorean theorem (for the magnitude) and the tangent function (for the direction). A non-scaled sketch is useful for visualizing the situation.
Applying the Pythagorean theorem leads to the magnitude of the resultant (R).
R2 = (30.0 m)2 + (4.0 m)2 = 916 m2
R = Sqrt(916 m2)
R = 30.3 meters
The angle theta in the diagram above can be found using the tangent function.
tangent(theta) = opposite/adjacent = (4.0 m) / (30.0 m)
tangent(theta) = 0.1333
theta = invtan(0.1333)
theta = 7.59 degrees
This angle theta is the angle between west and the resultant. Directions of vectors are expressed as the counterclockwise angle of rotation relative to east. So the direction is 7.59 degrees short of 180 degrees. That is, the direction is ~172 degrees.
A 30.0-g object moving to the right at 20.5 cm/s overtakes and collides elastically with a 13.0-g object moving in the same direction at 15.0 cm/s. Find the velocity of each object after the collision. (Take the positive direction to be to the right. Indicate the direction with the sign of your answer.)
Let m₁ and m₂ be the masses of the two objects, and v₁ and v₂ their initial velocities. So
m₁ = 30.0 g = 0.0300 kg
m₂ = 13.0 g = 0.0130 kg
v₁ = + 20.5 cm/s = 0.205 m/s
v₂ = + 15.0 cm/s = 0.150 m/s
and we want to find v₁' and v₂', the final velocities of either object after their collision.
Momentum is conserved throughout the objects' collision, so that
m₁v₁ + m₂v₂ = m₁v₁' + m₂v₂'
where v₁' and v₂' are the first and second object's velocities after the collision.
Kinetic energy is also conserved, so that
1/2 m₁v₁² + 1/2 m₂v₂² = 1/2 m₁(v₁')² + 1/2 m₂(v₂')²
or
m₁v₁² + m₂v₂² = m₁(v₁')² + m₂(v₂')²
From the first equation (omitting units), we have
0.0300 • 0.205 + 0.0130 • 0.150 = 0.0300 v₁' + 0.0130 v₂'
0.0810 = 0.0300 v₁' + 0.0130 v₂'
81 = 30 v₁' + 13 v₂'
From the second equation,
0.0300 • 0.205² + 0.0130 • 0.150² = 0.0300 (v₁')² + 0.0130 (v₂')²
0.00155 ≈ 0.0300 (v₁')² + 0.0130 (v₂')²
1.55 ≈ 30 (v₁')² + 13 (v₂')²
Solving both equations simultaneously gives two solutions, one of which corresponds to the initial conditions. The other yields
v₁' ≈ + 0.172 m/s
and
v₂' ≈ + 0.227 m/s
Why should people pay attention to scientists when making decisions?
A. Scientists are always correct.
B. Sclentists are the smartest people.
C. Scientists make the best decisions.
D. Scientists back up their statements with facts.
Answer:
D. Scientist back up their statements with facts.
Explanation:
The majority of the laws, theorems and thesis are base on with experiments. The follow different strategies for confirm the hypothesis with facts, one of the most famous models is the scientific method. That is a way of proof something in a trustworthy.
In the image is the resume about this method (graphical organizer).