Hi there!
(A)
A grinding wheel is the same as a disk, having moment of inertia of:
[tex]I = \frac{1}{2}MR^2[/tex]
Plug in the given mass and radius (REMEMBER TO CONVERT) to find the moment of inertia:
[tex]I = \frac{1}{2}(0.380)(0.085)^2 = 0.00137 kgm^2[/tex]
(B)
We can use the rotational equivalent of Newton's Second Law to calculate the needed torque:
Στ = Iα = τ₁ - τ₂
Begin by solving for the angular acceleration. Convert rpm to rad/sec:
[tex]\frac{1750r}{min} * \frac{1 min}{60 s} * \frac{2\pi rad}{1 r} = 183.26 rad/sec[/tex]
Now, we can use the following equation:
ωf = wi + αt (wi = 0 rad/sec, from rest)
183.26/5 = α = 36.65 rad/sec²
τ = Iα = 0.0503 Nm
Since there is a counter-acting torque on the system, we must begin by finding that acceleration:
[tex]\frac{1500r}{min} * \frac{1 min}{60 s} * \frac{2\pi rad}{1 r} = 157.08 rad/sec[/tex]
ωf = wi + αt
-157.08/55 = α = -2.856 rad/sec²
τ₂ = Iα = 0.0039 Nm
Now, calculate the appropriate torque using the above equation:
[tex]\Sigma\tau = \tau_1 - \tau_2[/tex]
[tex]\Sigma\tau + \tau_2 = \tau_1[/tex]
[tex]0.0503 + 0.0039 = \large\boxed{0.054 Nm}[/tex]
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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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.
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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trình bày những hiểu biết cơ bản về năng lượng
Answer:
I don't understand your language
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)
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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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
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
what is the specific latent heat of fusion of water?
Answer:
334
Explanation:
The octopus’s tentacle keeps _ right after it is bitten off ? a. Moving b. Breathing c. Growing
Answer:
The answer is A
Explanation:
The octopus’s tentacle keeps moving right after it is bitten off
Is the acceleration change or constnt?
Some amount of ideal gas with internal energy U was heated from 100^0C to 200^0C. We can predict that internal energy after heating in terms of U is:
The internal energy after heating in terms of U is 100U.
The given parameters;
initial temperature of the gas, T₁ = 100 ⁰Cfinal temperature of the gas, T₂ = 200 ⁰CAssuming a constant pressure, the internal energy of the ideal gas is equal to the change in the enthalpy of the ideal gas.
[tex]\Delta H = U \times \Delta T\\\\\Delta H = U (200 - 100)\\\\\Delta H = 100 U[/tex]
Thus, we can conclude that the internal energy after heating in terms of U is 100U.
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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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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???
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
How much force is required to raise a 0.2 kg mass?
Answer:
1.96 N
Explanation:
⇒This is your full answer
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.
(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:
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
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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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
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
name two examples where the cohesive force dominates over the adhesive force and vice versa
Cohesive forces are the forces that draw molecules of the same type together. Adhesive forces are those that draw molecules of various types together.
What is the difference between cohesive force and adhesive force?Cohesive forces are the forces that draw molecules of the same type together. Adhesive forces are those that draw molecules of various types together.
The force that draws molecules of the same substance together is called the cohesive force. The force that holds molecules of various substances together is known as the adhesive force.
Between molecules of the same substance, there are cohesive forces. There is a natural tendency to resist separation due to these intermolecular forces between like elements. Conversely, adhesive forces draw disparate molecules together.
In physics, cohesion refers to the intermolecular attraction that exists between two adjacent parts of a substance, especially one that is solid or liquid. A piece of matter is held together by this force. Adhesion is a term for the intermolecular forces that act when two dissimilar substances come into contact.
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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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An electron is held up against the force of gravity by the attraction of a fixed proton some distance above it. How far above the electron is the proton
5.08 m
Explanation:
The weight of the electron is being counteracted by the attractive electrostatic force exerted by the proton above it. We can write the force equation as follows:
[tex]m_eg = k_e\dfrac{Q_pQ_e}{r^2}[/tex]
where the Q's are the charges of the proton and electron, r is the distance between the particles, g is the acceleration due to gravity, [tex]m_e[/tex] is the mass of the electrons and [tex]k_e[/tex] is the Coulomb constant. So solving for r, we get
[tex]r^2 = k_e\dfrac{Q_pQ_e}{m_eg}[/tex]
Taking the square root of r^2, we then get the distance as
[tex]r = \sqrt{k_e\dfrac{Q_pQ_e}{m_eg}}[/tex]
The values are given as follows:
[tex]m_e = 9.11×10^{-31}\:\text{kg}[/tex]
[tex]g = 9.8\:\text{m/s}^2[/tex]
[tex]Q_p = Q_e = 1.60×10^{-19}\:\text{C}[/tex]
[tex]k_e = 8.99×10^9\:\text{N-m}^2\text{/C}^2[/tex]
Putting in all of these values in our equation for r,
[tex]r = \sqrt{\dfrac{(8.99×10^9\:\text{N-m}^2\text{/C}^2)(1.60×10^{-19}\:\text{C})^2}{(9.11×10^{-31}\:\text{kg})(9.8\:\text{m/s}^2)}}[/tex]
[tex]\:\:\:\:\:= 5.08\:\text{m}[/tex]
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
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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)
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