Answer:
a) P = 118.4 W, b) t = 7.9 10⁻⁵ s
Explanation:
a) Let's analyze this interesting exercise a bit, we suppose that all the laser
energy is used to heat the aluminum, we should calculate the energy necessary to bring the solid aluminum to the melting temperature and add the energy to carry out the change of solid state to liquid,
let's use the calorimeter equation
Q₁ = m c_e ΔT
and the energy of change of these solid to liquid (fusion process)
Q₂ = m L
the energy required to create the hole is
Q_ {total} = Q₁ + Q₂
if there are no losses this is the laser energy
E = Q_ {total}
The aluminun data c_e =9000 J/kgC, L = 322 103 J/kg, ρ = 2.7 103 kg/m3 , T₂ = 660C, T₀= 25C
Let's find the mass of the hole, which we approximate by a cylinder of diameter d = 0.25 mm = 0.25 10⁻³ m and a thickness of e = 1 mm = 1 10⁻³ m
let's use the concept of density
ρ = m / V
the volume of a cylinder is
V = π r² e = π (d²/4) e
we substitute
m = [tex]\rho \pi \frac{d^2 e}{4}[/tex]
let's calculate
m = π/4 2.7 10³ (0.25 10⁻³)² 1 10⁻³
m = 1,325 10⁻⁷ kg
we calculate the energy
E = 1,325 10⁻⁷ 900 (660 - 25) + 1,325 10⁻⁷ 322 10³
E = 7.57 10⁻² + 4.27 10⁻²
E = 1.184 10⁻¹ J
Let's use the power ratio
P = E / t
P = 0.1184 /1 10⁻³
P = 118.4 W
b) In this part they indicate that the laser power is P = 1500 W, find the time to deposit the energy to melt the aluminum
P = E / t
t = E / P
t = 0.1184 / 1500
t = 7.9 10⁻⁵ s
What number belongs where "X" is to properly balance this equation?
2 NaCl →
2 Na + Ecl2
04
o
2.
оо
Answer:
Option D: 1
Explanation:
The chemical equation given is;
2NaCl = 2Na + XCl2
We want to find the value of X.
On the left hand side, we can see we have 2 moles of both Na and Cl.
On the right hand side, we can see that we have 2 moles of Na and also 2 moles of Cl. Thus, the equation is balanced and as such X = 1
The statement "if I raise the temperature of
a cup of water, then an increased amount of
sugar will be dissolved" is an example of
A. an observation
B. a hypothesis.
C. a theory
What is one benefit to measuring your body’s flexibility?
A.
meeting the national requirement for flexibility
B.
determining your muscular strength
C.
tracking your flexibility improvements over time
D.
increasing the length of your life
Answer:
C
Explanation:
if you measure your body's flexibility then you can keep track of how flexible you have gotten over time
Low air pressure and warm temperatures over land are most likely to result in which of the following weather conditions or events?
A.Clear sunny skies
B. tropical hurricane
C. chance of snow
D.Cloudy skies with rain
g n diffraction, the formula for minima is given by a times s i n (theta )equals m lambda, where a is the width of the slit, theta is the angle of dispersion, m is the order, and lambda is the wavelength. For a wavelength of 630 nm, m equals 3, and a equals 5 times 10 to the power of negative 6 end exponent m. Calculate the angular spread in Degrees. Enter only the numerical value (i.e. omit the unit abbreviations when inputting your answer into Blackboard).
Answer:
θ = 22.2
Explanation:
This is a diffraction exercise
a sin θ = m λ
The extension of the third zero is requested (m = 3)
They indicate the wavelength λ = 630 nm = 630 10⁻⁹ m and the width of the slit a = 5 10⁻⁶ m
sin θ = m λ / a
sin θ = 3 630 10⁻⁹ / 5 10⁻⁶
sin θ = 3.78 10⁻¹ = 0.378
θ = sin⁻¹ 0.378
to better see the result let's find the angle in radians
θ = 0.3876 rad
let's reduce to degrees
θ = 0.3876 rad (180º /π rad)
θ = 22.2º
A constant applied force Fp of 11.0 N pushes a box with a mass=7 kg a distance x=15.0 m across a level floor. The coefficient of kinetic friction between the box and the floor is .110. Assuming the box starts from the rest, what is the final velocity vf of the box at 15.0 m point? If there were no friction between the box and the floor, what applied force Fnew would give the box the same final velocity?
We have that for the Question " constant applied force Fp of 11.0 N pushes a box with a mass=7 kg a distance x=15.0 m across a level floor. The coefficient of kinetic friction between the box and the floor is .110." it can be said that
the final velocity vf is
[tex]vf=3.83m/s[/tex]
and the applied force Fnew is
[tex]F_{new}=3.43N[/tex]
From the question we are told
A constant applied force Fp of 11.0 N pushes a box with a mass=7 kg a distance x=15.0 m across a level floor. The coefficient of kinetic friction between the box and the floor is .110. Assuming the box starts from the rest, what is the final velocity vf of the box at 15.0 m point? If there were no friction between the box and the floor, what applied force F new would give the box the same final velocity?
Generally the equation for the Force is mathematically given as
F_p-\mu mg=ma
Therefore
11-0.110*7*9.8=7*a
a=0.49m/s^2
Using Newtons equation
v^2=u^2+2as
v^2=0+2*0.49*15
v=3.83m/s
Therefore
F=ma
F=0.49*7
F_{new}=3.43N
Therefore
the final velocity vf is
[tex]vf=3.83m/s[/tex]
and the applied force Fnew is
[tex]F_{new}=3.43N[/tex]
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Calculate the volume occupied by a glass cup having a mass of 260 g knowing that the
density of glass is equal to 2.6 g/cm3
Answer:
100 milliliters
Explanation:
a particle moves along of the x_axis according to the equation X=2t+3t^2, whare x is in m and t is in second. calcualt the instantaneous velocity and the instantaneous acceleration in t=3s
Answer:
Instantaneous velocity [tex]= 20[/tex] meter per second
Instantaneous acceleration [tex]= 6[/tex] meter per second square
Explanation:
Given equation of distance X = [tex]2t+3t^2[/tex]
Instantaneous velocity [tex]= \frac{dX}{dt}[/tex] [tex]= 2 + 6 t[/tex]
Substituting the value of t = 3 seconds, we get -
[tex]\frac{dX}{dt} = 2 + 6*3 = 20[/tex] meter per second
Instantaneous acceleration [tex]= \frac{d^2X}{dt^2}[/tex] [tex]= 6[/tex] meter per second square
It has been shown that the half-life for this radioactive isotope is 20 years. In the year 2000, an archaeology team unearths pottery and is using this isotope for radiometric dating to place the age of the pottery. It is shown that 95% of the nuclei have decayed. How much mass has decayed? How much mass is left?
I'd prefer to be shown a step-by-step on how to solve for these questions. I do better with seeing the step-by-step, and can retain the information better.
Answer:
(1/2)*n = .05 by the definition of half-life where n is the number of half-lives
n ln .5 = ln .05
n = ln .05 / ln .5 = 4.32 number of half-lives
So 4.32 * 20 = 86.4 years has passed
Actually, they only want the mass left. However, all that has changed is that
95% of the original radioactive atoms have changed to a different form of about the same amount of mass. The amount of mass remaining would be about the same. Also, one doesn't know the percentage of radioactive atoms
that formed the original mass.
All of the following are characteristics of a laser diode except
Answer:
D
Explanation:
Given that all of the following are characteristics of a laser diode except
Solution.
A laser diode emit light of a single colour. That is, it emits a monochromatic light in which the light emitted monochromatically will definitely be coherent. That is, a light with a single wavelength emitted by a wide wavelength.
Also, all diode have positive and negative junction which is known as pn junction.
The incorrect among all the options is option D which is the answer.
!Please help fast!!*18 pts*!
How is light amplified in a laser?
A. Photons "leak" through a partically reflecting mirror, causing them to travel in step.
B. Integrated circuits in a laser amplify the sound produced by photon emission.
C. Photons collide with gas particles, multiply, and reflect back and forth in a tube.
D. Electric current is amplified and directed into gas particles, which emit photons.
Answer:
A.
Explanation:
Some of these photons are absorbed by the atoms in the ground state and the photons are lost to the laser process. However, some photons cause stimulated emission in excited-state atoms, releasing another coherent photon. In effect, this results in optical amplification
Definition of continental polar
cold, dry, and stable air masses .
There is only one temperature where the Celsius and Fahrenheit thermometers will read the same and no conversions need to be made. What is it?
A. -25 degrees
B. -40 degrees
C. 25 degrees
D. 0 degrees
Answer:
-40 degrees
Explanation:
I just took the Temperature Quiz and got it right. :)
a violin is less than 0.5 m long. a bass fiddle is more than 1.5 m long. which instrument do you expect to be able to play notes with a lower pitch and why?
Explanation:
When there is a high frequency sound the speed of the vibrations is faster and makes a high pitch sound. When there is a low frequency sound the speed of the vibrations is slower and makes a lower pitch sound.
What is R2 in the circuit?
WILL GIVE BRAINLIEST !!!!
Answer:
1. Rₑq = 4 Ω
2. R₂ = 6 Ω
3. Vₜ = 12 V, V₁ = 12 V, V₂ = 12 V
4. Iₜ = 3 A, I₁ = 1 A, I₂ = 2 A
Explanation:
1. Determination of the equivalent resistance
Voltage (V) = 12 V
Current (I) = 3 A
Resistance (Rₑq) =?
V= IRₑq
12 = 3 × Rₑq
Divide both side by 3
Rₑq = 12 / 3
Rₑq = 4 Ω
Thus, the equivalent resistance (Rₑq) = 4 Ω
2. Determination of R₂.
Equivalent resistance (Rₑq) = 4 Ω
Resistance 1 (R₁) = 12 Ω
Resistance 2 (R₂)
Since the resistor are in parallel arrangement, the value of R₂ can be obtained as follow:
Rₑq = R₁ × R₂ / R₁ + R₂
4 = 12 × R₂ / 12 + R₂
Cross multiply
4(12 + R₂) = 12R₂
48 + 4R₂ = 12R₂
Collect like terms
48 = 12R₂ – 4R₂
48 = 8R₂
Divide both side by 8
R₂ = 48 / 8
R₂ = 6 Ω
3. Determination of the total voltage (Vₜ), V₁ and V₂.
From the question given above, the total voltage is 12 V
Since the resistors are arranged in parallel connection, the same voltage will go through them.
Thus,
Vₜ = V₁ = V₂ = 12 V
4. Determination of the total current (Iₜ), I₁ and I₂
From the question given above, the total current (Iₜ) is 3 A
Next, we shall determine I₁. Since the resistors are arranged in parallel connection, different current will pass through each resistor respective.
Vₜ = V₁ = 12 V
R₁ = 12 Ω
I₁ =?
V₁ = I₁R₁
12 = I₁ ×12
Divide both side by 12
I₁ = 12 / 12
I₁ = 1 A
Next, we shall determine I₂. This can be obtained as follow:
Iₜ = 3 A
I₁ = 1 A
I₂ =?
Iₜ = I₁ + I₂
3 = 1 + I₂
Collect like terms
I₂ = 3 – 1
I₂ = 2 A
Find the velocity of an object that has a mass of 500x10-6 kg and a charge of 1pc if it starts from
rest and passes through a potential difference of 120kV
Answer:
v = 4.8 10⁻⁴ m / s
Explanation:
To solve this exercise we can use the concepts of energy. In this case the potential energy is transformed into kinetic energy
U = K
q V = ½ m v²
v = [tex]\sqrt { \frac{2qV}{m} }[/tex]
in the exercise they indicate the value of the charge q₁ = 1 pC = 1 10⁻¹² C
let's calculate
v = [tex]\sqrt{ \frac{2 \ 1 \ 10^{-12} 120 \ 10^3}{500 ^{2} }[/tex]
v = 4.8 10⁻⁴ m / s
A piano tuner stretches a steel piano wire with a tension of 765 N. The steel wire has a length of 0.800 m and a mass of 6.00 g . What is the frequency f1 of the string's fundamental mode of vibration
Answer:
the frequency of the fundamental mode of vibration is 199.6 Hz
Explanation:
Given;
tension of the piano wire, T = 765 N
length of the steel wire, L = 0.8 m
mass of the steel wire, m = 6.00 g = 6 x 10⁻³ kg
The frequency of the fundamental mode of vibration is calculated as;
[tex]f_o = \frac{1}{2l} \sqrt{\frac{T}{\mu} }[/tex]
where;
μ is the mass per unit length [tex]= \frac{6.0 \times 10^{-3}}{0.8} = 7.5 \times 10^{-3} \ kg/m[/tex]
[tex]f_o = \frac{1}{2l} \sqrt{\frac{T}{\mu} } \\\\f_o = \frac{1}{2\times 0.8} \sqrt{\frac{765}{7.5 \times 10^{-3}} } \\\\f_o = 199.6 \ Hz[/tex]
Therefore, the frequency of the fundamental mode of vibration is 199.6 Hz
A 4 kg particle moves at a constant speed of 2.5 m/s around acircle of radius 2 m. What is its angular momentum about the center of the circle? Answerin units of kg · m2/s. What is its moment of inertia about an axis through the center ofthe circle and perpendicular to the plane of the motion? Answer inunits of kg · m2. What is t
Explanation:
Given that,
Mass of the particle, m = 4 kg
Speed of the particle, v = 2.5 m/s
The radius of the circle, r = 2 m
We need to find the angular momentum about the center of the circle. The formula for the angular momentum is given by :
[tex]L=mvr[/tex]
Substitute all the values,
[tex]L=4\times 2.5\times 2\\\\L=20\ kg{\cdot}m^2s[/tex]
So, the angular momentum of the particle is 20 kg-m² s.
a pool and stops at the
Which best describes his
motion?
A. Linear
B. Projectile
C. Vibrational
In Linear motion the swimmer swims
Answer: A
Explanation: Linear motion.
1 ) when a ball is projected upwords its time of rising is ...............the time of falling .
a) greater than b) smaller than c) equal to d ) double
2 ) when an object falls freely under the effect of gravity , the distance moved is
a ) directly proportional to time
b ) inversely proportional to time
c ) directly proportional to square of time
d ) inversely proportional to square of time.
Answer:
correct answer is C
Explanation:
In this exercise, you are asked to complete the sentences so that the sentence makes sense.
1) in projectile launching, the only force that acts is gravity in the vertical direction, so the time of going up is EQUAL to the time of going down
correct answer C
2) when a body falls freely, the acceleration is the ratio of gravity, therefore if it starts from rest, its height is
y = v₀ t - ½ gt²
v₀ = 0
y = -1/2 g t²
so the position is not proportional to the square of the time
correct answer is C
A 2.60 kg lion runs at a speed of 5.00 m/s until he sees his prey. The lion then speeds up 8.00 m/s to catch it. How much work did do after he speeds up?
Answer: 50.7 J
Explanation:
Given
mass of lion is [tex]m=2.6\ kg[/tex]
The initial speed of the lion is [tex]v_1=5\ m/s[/tex]
increased speed of lion is [tex]v_2=8\ m/s[/tex]
Initially, its kinetic energy is [tex]K_1=\frac{1}{2}mv_1^2[/tex]
Final kinetic energy [tex]k_2=\frac{1}{2}mv_2^2[/tex]
work did by lion after speed up is [tex]k_2-k_1[/tex]
[tex]\Rightarrow W=\dfrac{1}{2}\times 2.6[8^2-5^2]\\\\\Rightarrow W=1.3\times [39]=50.7\ J[/tex]
A circular loop of radius 13 cm carries a current of 13 A. A flat coil of radius 0.94 cm, having 58 turns and a current of 1.9 A, is concentric with the loop. The plane of the loop is perpendicular to the plane of the coil. Assume the loop's magnetic field is uniform across the coil. What is the magnitude of (a) the magnetic field produced by the loop at its center and (b) the torque on the coil due to the loop
Answer:
[tex]6.28\times 10^{-5}\ \text{T}[/tex]
[tex]1.92\times 10^{-6}\ \text{Nm}[/tex]
Explanation:
[tex]\mu_0[/tex] = Vacuum permeability = [tex]4\pi 10^{-7}\ \text{H/m}[/tex]
[tex]I_l[/tex] = Current in circular loop = 13 A
[tex]r_l[/tex] = Radius of circular loop = 13 cm
[tex]N[/tex] = Number of turns = 58
[tex]r_c[/tex] = Radius of coil = 0.94 cm
[tex]I_c[/tex] = Current in coil = 1.9 A
[tex]\theta[/tex] = Angle between loop and coil = [tex]90^{\circ}[/tex]
Magnitude of magnetic field in circular loop
[tex]B_l=\dfrac{\mu_0I_l}{2r_l}\\\Rightarrow B_l=\dfrac{4\pi 10^{-7}\times 13}{2\times 13\times 10^{-2}}\\\Rightarrow B_l=6.28\times 10^{-5}\ \text{T}[/tex]
The magnetic field produced by the loop at its center is [tex]6.28\times 10^{-5}\ \text{T}[/tex].
Torque is given by
[tex]\tau=\pi NI_cr_c^2B_l\sin\theta\\\Rightarrow \tau=\pi 58\times 1.9\times (0.94\times 10^{-2})^2\times 6.28\times 10^{-5}\sin90^{\circ}\\\Rightarrow \tau=1.92\times 10^{-6}\ \text{Nm}[/tex]
The torque on the coil due to the loop [tex]1.92\times 10^{-6}\ \text{Nm}[/tex].
customer complains of an aluminum foil mixed with his salad? what will you do?
Answer:
offer them a refund or a remake/ replacement of food item whilst apologizing sincerely
what is the main cause of the seasons
Which of the following is a true statement for a child's toy spinning in a circle at constant speed?
a) The speed is constant, the velocity is constant, and the angular velocity is constant. b) The speed is constant, the velocity is not constant, and the angular velocity is constant. c) The speed is constant, the velocity is not constant, and the angular velocity is not constant. d) The speed is constant, the velocity is constant, and the angular velocity is not constant.
explain your answer.
Answer:
B
Explanation:
I am pretty sure it is B as the speed is obviously constant but the velocity is not constant as it defines as the rate of speed AND DIRECTION meaning that it is not constant as it always changes direction. And angular velocity is constant.
According to Newton’s second law of motion, weight depends on an object’s mass and the net force acting on the object. True or false
Answer:
true..
Explanation:
Newton's 2nd law of motion is greater the mass of an object the more force it will take to accelerate the object
According to Newton’s second law of motion, weight depends on an object’s mass and the net force acting on the object. The given statement is true.
What is force?Force is defined as the push or pull applied to the body. Sometimes it is used to change the shape, size, and direction of the body.
The following equation help to understand the statement;
Force is defined as the product of mass and acceleration. Its unit is Newton.
F=ma
F=mg
W=mg
The weight of an item is determined by its mass and the net force exerted on it, according to Newton's second rule of motion. The provided assertion is correct.
Hence,the given statement is true.
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what is the minimum effort required to raise the block?
Answer:
2000 N.
Explanation:
From the question given above, the following data were obtained:
Load (L) = 8000 N
Mechanical advantage (MA) = 4
Effort (E) =?
The mechanical advantage of a machine is simply defined as:
Mechanical advantage = Load / Effort
MA = L / E
With the above formula, we can obtain the effort used to raise the load of 8000 N as follow:
Load (L) = 8000 N
Mechanical advantage (MA) = 4
Effort (E) =?
MA = L / E
4 = 8000 / E
Cross multiply
4 × E = 8000
Divide both side by 4
E = 8000 / 4
E = 2000 N
Thus, the effort used to raised the load is 2000 N.
A student is provided with a rubber cylinder and a patch of synthetic fur. The rubber cylinder and the patch are electrically neutral. The student rubs the cylinder back and forth along the fur. A short time later, after the cylinder and fur have been placed on insulating stands, the student determines that the fur has a net negative electric charge. Before the patch of fur attained its net negative charge, it was considered to be electrically neutral. Which of the following claims, with appropriate evidence, is correct about the distribution of charge in the patch of fur before the charging process?
a. It is an isolated system.
b. It is a closed system.
c. It is an open system.
d. The type of system cannot be determined unless information is known about the net force exerted on the system at any given time.
Answer:
Option b ( It is a closed system) is the appropriate answer.
Explanation:
The mass transfer isn't made on a platform. There seems to be no mass transfer, the mechanism can't be separated as power lines will interfere beyond the physical boundaries including its fur patch.The mechanism can't however be separated and, while the mass transfer is indeed not present, several field lines will communicate well outside the mechanism.The other options are not linked to the situation in question. Thus, the answer is correct.
A block of wood and a block of aluminum have been sitting out for a while. How do their temperatures compare?
Answer:
Block of aluminum
Explanation:
The block of aluminum because of the conductivity, and is a metal, so it gets hotter faster
The temperature of wood and the aluminium will depend upon thier thermal coductivity.
What is thermsal conductivity?The thermal conductivity of any material is defined as the amount of heat from a material can flow in a unit area per unit degree centigrade for a unit distance.
The thermal conductivity of wood is around 0.90 to 0.197 w/mk and that of aluminium is around 88 to 251 w/mk.
We can see that the aluminium block will absorb much amount of heat as compared to the wood block. Because the thermal conductivity of aluminium is much higher then the wood.
Hence temperature of wood and the aluminium will depend upon thier thermal coductivity.
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a car is travelling at 18m/s accelerates ti 30m/s in 3seconds. what's the acceleration of the car
[tex] \Large {\underline { \sf {Required \; Solution :}}}[/tex]
We have ―
Initial velocity, u = 18 m/sFinal velocity, v = 30 m/sTime taken, t = 3 secondsWe've been asked to calculate acceleration.
[tex]\qquad \implies\boxed{\red{\sf{ a = \dfrac{v-u}{t} }}}\\[/tex]
a denotes accelerationv denotes final velocityu denotes initial velocityt denotes time[tex] \twoheadrightarrow \quad \sf {a = \dfrac{30-18}{3} \; ms^{-2} } \\ [/tex]
[tex] \twoheadrightarrow \quad \sf {a =\cancel{ \dfrac{12}{3} \; ms^{-2} }} \\ [/tex]
[tex]\twoheadrightarrow \quad \boxed{\red{\sf{ a = 4 \; ms^{-2} }}}\\[/tex]
Therefore, acceleration of the car is 4 m/s².