Element is
[tex]\boxed{\sf {}^{27}Al_{13}}[/tex]
Atomic number=13Mass number=27[tex]\\ \sf\longmapsto No\:of\:Protons=Atomic \:Number=13[/tex]
And[tex]\\ \sf\longmapsto No\:of\:Neutrons=Mass\:number-Atomic\:Number[/tex]
[tex]\\ \sf\longmapsto No\:of\:Neutrons=27-13[/tex]
[tex]\\ \sf\longmapsto No\:of\:Neutrons=14[/tex]
And
[tex]\\ \sf\longmapsto No\:of\:electrons=No\:of\:Protons=13[/tex]
Why is it advised not to hold the thermometer by its bulb while reading it?
A wheel of radius 25cm has eight spokes. It is mounted on a fixed axle and is rotating at a constant angular speed w. You shoot a 20cm long arrow parallel to the axle through the wheel at a speed of 6m/s. The arrow and the spokes are supposed to be thin. Calculate the maximum value of w ( in rad/second and in rev/second) so that the arrow just goes through without hitting any of the spokes. Does it matter where between the axle and the rim of the wheel you aim? If so, what is the best location?
Explanation:
We will assume that the rim of the wheel is also very thin, like the spokes. The distance s between the spokes along the rim is
[tex]s = \frac{1}{8}C = \frac{1}{8}(2\pi)(0.25\:\text{m}) = 0.196\:\text{m}[/tex]
The 20-cm arrow, traveling at 6 m/s, will travel its length in
[tex]t = \dfrac{0.2\:\text{m}}{6\:\text{m/s}} = \dfrac{1}{30}\:\text{s}[/tex]
The fastest speed that the wheel can spin without clipping the arrow is
[tex]v = \dfrac{s}{t} = \dfrac{0.196\:\text{m}}{\left(\dfrac{1}{30\:\text{s}}\right)} = 5.9\:\text{m/s}[/tex]
The angular velocity [tex]\omega[/tex] of the wheel is given by
[tex]\omega = \dfrac{v}{r} = \dfrac{5.9\:\text{m/s}}{0.25\:\text{m}} = 23.6\:\text{rad/s}[/tex]
In terms of rev/s, we can convert the answer above as follows:
[tex]23.6\:\dfrac{\text{rad}}{\text{s}}×\dfrac{1\:\text{rev}}{2\pi\:\text{rad}} = 3.8\:\text{rev/s}[/tex]
As you probably noticed, I did the calculations based on the assumption that I'm aiming for the edge of the wheel because this is the part of the wheel where a point travels a longer linear distance compared to ones closer to the axle, thus giving the arrow a better chance to pass through the wheel without getting clipped by the spokes. If you aim closer to the axle, then the wheel needs to spin slower to allow the arrow to get through without hitting the spokes.
Answer:omega=23.56... rad/s
Explanation:for the arrow to pass without hitting the 8 spokes
taking the spokes thickness to be a point along the spokes linear motion path
lets calculate the time athe arrow pass point length of the wire 0.25m and it's speed(6m/s)
t=0.25m÷6m/s=0.0333...s
so every spoke around the wheel must move replacing each other's position so distribution of eight spokes=2π÷8=0.78... rad so using as angular displacement and t=0.033s then omega=∅/t=0.78/0.033=23.56rad/s
*yes
*space between spokes
Who should you invite to the meeting?
—-
Answer
Irma
Explanation:
You should invite Irma to the meeting because she is in Charlotte and she also visited after 10/24/20
MULTIPLE CHOICE
What is the role of the Sun in a forest ecosystem?
What is the Role of the sun in a forest ecosystem?
Answer:
It is to produce sunlight in the forest plants
A light beam inside a container of some liquid hits the surface of the liquid/air interface. Depending on the angle, the light beam may or may not be able to get out into the air medium. At what angle will the beam of light be totally reflected back into the liquid in the container
Answer:
Following are the solution to the given question:
Explanation:
Applying the Snell Law:
when is the liquid's refractive index, is the air's refractive index.
the liquid's refractive index, the air's index of refraction.
It is the limiting case when , Inside the interphase of two mediums, light is scattered. Thus,
[tex]n_l \sin \theta_l = n_a \sin 90^\circ = n_a[/tex]
[tex]\theta_l = \arcsin \dfrac{n_a}{n_l} =\arcsin \dfrac{1}{1.38} = 46.4^\circ[/tex]
From the incident angles [tex]\theta_l[/tex] is greater than 46.4°, that is the light reflected back into the liquid.
prove that young modulus of elasticity and pressure have the same dimensions
Answer:
The dimensions of Young's Modulus, as well as material stress, are the same as pressure because stress is like pressure in a solid, except with some key differences that warrant the use of different terminology.
A rock weighing 20 N (mass = 2 kg) is swung in a horizontal circle of radius 2 m at a constant speed of 6 m/s. What is the tension in the cord?
Answer:
The tension in the cord provides by centripetal force
T = Fc
= mv^2/r
= 2kg ( 6)^2/2
=36 N
what is a main difference between local units and standard units?
Explanation:
local units doesn't give accurate measurement
but standard units give accurate measurement
name a device that converts mechanical energy into electrical energy.
Answer:
Electric generator is the device that converts mechanical energy into electrical energy
What are the systems of units? Explain each of them.
THERE ARE COMMONLY THREE SYSTEMS OF UNIT. THEY ARE:-
• CGS System- (Centimeter-Gram-Second system) A metric system of measurement that uses the centimeter, gram and second for length, mass and time.
• FPS System- (Foot–Pound–Second system).
The system of units in which length is measured in foot , mass in pound and time in second is called FPS system. It is also known as British system of units.
• MKS System- (Meter-Kilogram-Second system) A metric system of measurement that uses the meter, kilogram, gram and second for length, mass and time. The units of force and energy are the "newton" and "joule."
Vector a has a magnitude of 8 and makes an angle of 45 with positive x axis vector B has also the same magnitude of 8 units and direction along the
Answer:
prove that Sin^6 ϴ-cos^6ϴ=(2Sin^2ϴ-1)(cos^2ϴ+sin^4ϴ)
please sove step by step with language it is opt maths question
find the equivalent resistance of this circuit
Answer:
Req = 564 Ω
Explanation:
The equivalent resistance between R1 and R2:
1/R =1/R1 + 1/R2
1/R =1/960 + 1/640
1/R = 1/384
R = 384
Now, the equivalent resistance between R and R3:
Req = 384 + 180
Req = 564 Ω
Imagine a spaceship traveling at a constant speed through outer space. The length of the ship, as measured by a passenger aboard the ship, is 28.2 m. An observer on Earth, however, sees the ship as contracted by 16.1 cm along the direction of motion. What is the speed of the spaceship with respect to the Earth
[tex]3.20×10^7\:\text{m/s}[/tex]
Explanation:
Let
[tex]L = 28.2\:\text{m}[/tex]
[tex]L' = 28.2\:\text{m} - 0.161\:\text{m} = 28.039\:\text{m}[/tex]
The Lorentz length contraction formula is given by
[tex]L' = L\sqrt {1 - \left(\dfrac{v^2}{c^2}\right)}[/tex]
where L is the length measured by the moving observer and L' is the length measured by the stationary Earth-based observer. We can rewrite the above equation as
[tex]\sqrt {1 - \left(\dfrac{v^2}{c^2}\right)} = \dfrac{L'}{L}[/tex]
Taking the square of the equation, we get
[tex]1 - \left(\dfrac{v^2}{c^2}\right) = \left(\dfrac{L'}{L}\right)^2[/tex]
or
[tex]1 - \left(\dfrac{L'}{L}\right)^2 = \left(\dfrac{v}{c}\right)^2[/tex]
Solving for v, we get
[tex]v = c\sqrt{1 - \left(\dfrac{L'}{L}\right)^2}[/tex]
[tex]\:\:\:\:=(3×10^8\:\text{m/s})\sqrt{1 - \left(\dfrac{28.039\:\text{m}}{28.2\:\text{m}}\right)^2}[/tex]
[tex]\:\:\:\:=3.20×10^7\:\text{m/s} = 0.107c[/tex]
Two hockey players are about to collide on the ice. One player has a mass of
70 kg and is traveling at 1.4 m/s north. The other has a mass of 75 kg and is
traveling at 1.0 m/s south. The system consists of the two hockey players.
According to the law of conservation of momentum, what is the total
momentum of the system after they collide? Assume the collision is an
elastic collision.
A. 173 kg.m/s south
B. 23 kg-m/s north
C. 23 kg.m/s south
D. 173 kg.m/s north
Answer:
B. 23 kg*m/s north
Explanation:
p_1 = p_2
(m*v)_1 + (m*v)_2 = (m*v)_1' + (m*v)_2'
(70kg*1.4m/s)+(75kg*-1.0m/s) = p_2
(98kg*m/s)+(-75kg*m/s) = 23kg*m/s north
B. 23 kg*m/s north
Two hockey players are about to collide on the ice, so the total momentum of the system when they collide is 23 kg m/s. Hence, option B is correct.
What is momentum?The result of a particle's mass and velocity is momentum. It has both magnitude and direction because momentum is a vector quantity. According to Isaac Newton's second law of motion, the force pushing a particle has an equal and opposite effect on the temporal rate at which its momentum changes.
[tex]Momentum (p)= Mass(m)*Velocity(v)[/tex]
The given values according to the question is :
p₁ = p₂
(m × v)₁+ (m × v)₂ = (m × v)₁' + (m × v)₂'
(70 kg × 1.4 m/s) + (75 kg) × (-1.0 m/s) = p₂
(98 kg m/s) + (- 75 kg m/s) = 23 kg m/s North
Therefore, the total momentum after collision is 23 kg m/s North.
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A 1.8-mole sample of an ideal gas is allowed to expand at a constant temperature of 250 K. The initial volume is 34 L and the final volume is 80 L. How much work does the gas perform on its container? Let the ideal-gas constant R = 8.314 J/(mol • K).
Answer:
3201.304 J
Explanation:
Use ideal gas equation to initial stage:
PV=nRT
P * 0.034 = 1.8 * 8.314 * 250
P = 110038.2353 Pa
Use ideal gas equation to final stage:
PV=nRT
P * 0.08 = 1.8 * 8.314 * 250
P = 46766.25 Pa
Process is isothermal (constant temperature )
Therefore,
Work= C ln (V2/V1)
(P1V1=P2V2=C)
(Above equation is taken by integration of P.dv)
Work = P1V1 ln (V2/V1) = P2V2 ln (V2/V1)
By substituting above data to the equation:
Work = (110038.2353 * 0.034) * ln (0.08/0.034)
Work = 3201.304 J
elastic wire extend by 1.ocm when a load on 20g range from It, what additional load will it be required Cause the futher extension of 2.0cm
Answer:
40g
Explanation:
20g range > 1.0cm
Therefore,
40g range > 2.0cm
How is the sun used to make food?
Answer:
Plants use a process called photosynthesis to make food. During photosynthesis, plants trap light energy with their leaves. Plants use the energy of the sun to change water and carbon dioxide into a sugar called glucose. Glucose is used by plants for energy and to make other substances like cellulose and starch.
Thank you
Answer:
Plants use a process called photosynthesis to make food. During photosynthesis, plants trap light energy with their leaves. Plants use the energy of the sun to change water and carbon dioxide into a sugar called glucose.
A brass road is 2cm long at instance to what is the lense for a temperature rise of 100k, If the expansivity of brass is 18x10^-6/k^-1
The length of the brass at a temperature rise of 100 K is 2.0036 m
From the question given above, the following data were obtained:
Original length (L₁) = 2 m
Temperature rise (ΔT) = 100 K
Coefficient of linear expansion (α) = 18×10¯⁶ K¯¹
Final length (L₂) =?The final length of the brass can be obtained as follow:
α = L₂ – L₁ / L₁ΔT
18×10¯⁶ = L₂ – 2 / (2 × 100)
18×10¯⁶ = L₂ – 2 / 200
Cross multiply
L₂ – 2 = 18×10¯⁶ × 200
L₂ – 2 = 0.0036
Collect like terms
L₂ = 0.0036 + 2
L₂ = 2.0036 m
Thus, the length of the brass at a temperature rise of 100 K is 2.0036 m
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Which of the following statement regarding electromagnetic waves is FALSE?
a) In vacuum, the wave travels in a straight line.
b) The energy in the wave is proportional to the product of the electric and magnetic fields.
c) The speed of the wave in vacuum is given by c = 1/sqrt ε0μ0
d) The magnetic field is much greater in magnitude than the electric field
Answer:
hi
Explanation:
your answer is
The energy in the wave is proportional to the product of the electric and magnetic fields.
A 80 kg bungee jumper is on a bridge that is 100 meters above a river. Attached to the jumper is a bungee cord that is 50 meters long. After jumping off of the bridge, the jumper reaches a position that is 10 meters above the river when the bungee cord is at its maximum stretch.
Required:
a. How much energy is stored in the bungee cord at that maximum stretch?
b. What is the spring force constant of the bungee cord?
Answer:
a) 70,560 J
b) 88.2 N/m
Explanation:
The spring potential will equal the change in gravity potential
PS = PE = mgh = 80(9.8)(100 - 10) = 70,560 J
PS = ½kx²
k = 2PS/x² = 2(70560)/(100 - 50 - 10)² = 88.2 N/m
What are the multiple of meter ?
What are the sub multiple of meter?
Answer:
To cover a larger distance we use km(kilometre) , hm (hectometre) , and dac(decametre). These are called the multiples of Metre. For the distance is smaller , we use Dm (decimetre , cm(centimetre) and mm (millimetre) . These are called the submultiples of
Calculate the equivalent of 30 degrees Celsius and 50 degrees Celsius on a Kelvin
[tex]\boxed{\sf 1°C=273K}[/tex]
Sol:-1
[tex]\\ \sf\longmapsto 30°C[/tex]
[tex]\\ \sf\longmapsto 273+30[/tex]
[tex]\\ \sf\longmapsto 303K[/tex]
Sol:-2
[tex]\\ \sf\longmapsto 50°C[/tex]
[tex]\\ \sf\longmapsto 50+273[/tex]
[tex]\\ \sf\longmapsto 323K[/tex]
what is liquid pressure? and tell me its si unit please
The SI unit of pressure is the pascal: 1Pa=1N/m2 1 Pa = 1 N/m 2 . Pressure due to the weight of a liquid of constant density is given by p=ρgh p = ρ g h , where p is the pressure, h is the depth of the liquid, ρ is the density of the liquid, and g is the acceleration due to gravity.
A sound wave made up of large number of unrelated frequencies superposted on each other is
Since the frequencies are unrelated, and there are a large number of them, I'll say this represents an example of noise.
Kelsey the triathelete swims 1.5 km east, then bikes 40 km north, and then runs 10 km west. Which choice gives the
correct solution for the resultant?
R2 = 402 – 8,52
R2 = 402 - 102 - 2(40)(1.5) cos 10
R2 = 102 - 40
R2 = 10- - 402 – 2(1.5)(10) cos 40
Answer:
Hey,. its a simple question. hope you learn from the solution. check attached picture
Explanation:
The fact that Voyager 10 continues to speed out of the solar system, even though its rockets have no fuel, is an example of Group of answer choices Newton's third law of motion. Newton's second law of motion. Newton's first law of motion. the universal law of gravitation. none of these
Answer:
The universal law of gravitation.
PE = m * G M / R^2 potential energy of mass m due to attractive forces
If the kinetic energy of mass m is greater than the energy due to the attractive masses then then mass m can continue indefinitely away from the attracting masses.
1.An elevator is ascending with constant speed of 10 m/s. A boy in the elevator throws a ball upward at 20 m/ a from a height of 2 m above the elevator floor when the elevator floor when the elevator is 28 m above the ground.
a. What's the maximum height?
b. How long does it take for the ball to return to the elevator floor?
(a) The maximum height reached by the ball from the ground level is 75.87m
(b) The time taken for the ball to return to the elevator floor is 2.21 s
The given parameters include:
constant velocity of the elevator, u₁ = 10 m/sinitial velocity of the ball, u₂ = 20 m/sheight of the boy above the elevator floor, h₁ = 2 mheight of the elevator above the ground, h₂ = 28 mTo calculate:
(a) the maximum height of the projectile
total initial velocity of the projectile = 10 m/s + 20 m/s = 30 m/s (since the elevator is ascending at a constant speed)
at maximum height the final velocity of the projectile (ball), v = 0
Apply the following kinematic equation to determine the maximum height of the projectile.
[tex]v^2 = u^2 + 2(-g)h_3\\\\where;\\\\g \ is \ the \ acceleration \ due \ to\ gravity = 9.81 \ m/s^2\\\\h_3 \ is \ maximum \ height \ reached \ by \ the \ ball \ from \ the \ point \ of \ projection\\\\0 = u^2 -2gh_3\\\\2gh_3 = u^2 \\\\h_3 = \frac{u^2}{2g} \\\\h_3 = \frac{(30)^2}{2\times 9.81} \\\\h_3 = 45.87 \ m[/tex]
The maximum height reached by the ball from the ground level (h) = height of the elevator from the ground level + height of he boy above the elevator + maximum height reached by elevator from the point of projection
h = h₁ + h₂ + h₃
h = 28 m + 2 m + 45.87 m
h = 75.87 m
(b) The time taken for the ball to return to the elevator floor
Final height of the ball above the elevator floor = 2 m + 45.87 m = 47.87 m
Apply the following kinematic equation to determine the time to return to the elevator floor.
[tex]h = vt + \frac{1}{2} gt^2\\\\where;\\\\v \ is \ the \ initial \ velocity \ of \ the \ ball \ at \ the \ maximum \ height = 0\\\\h = \frac{1}{2} gt^2\\\\gt^2 = 2h\\\\t^2 = \frac{2h}{g} \\\\t = \sqrt{\frac{2h}{g}} \\\\t = \sqrt{\frac{2\times 47.87}{9.81}} \\\\t = 2.21 \ s[/tex]
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Megan accelerates her skateboard from 0 m/s to 8 m/s in 2 seconds. What is the magnitude of the acceleration of the skateboard?
O 8 m/s^2
O 16 m/s^2
O 2 m/s^2
O 4 m/s^2
Answer:
chk picture for eqn
Explanation:
The double bond between two oxygen atoms (a molecule of oxygen air) has
two characteristics. What are they?
A. Four valence electrons are shared.
B. A metallic bond is formed.
C. Valence electrons are shared between oxygen atoms.
D. An ionic bond is formed.
Answer:
valance electrons are shared between oxygen atoms.. making them have eight in the outer most shells.
I hope this helps
why the stone moves away when the string is broken rotation
Answer:
When a stone is going around a circular path, the instantaneous velocity of stone is acting as tangent to the circle. When the string breaks, the centripetal force stops to act. Due to inertia, the stone continues to move along the tangent to circular path. So, the stone flies off tangentially to the circular path
Answer:
when the string's rotation is broken, there will be no centripetal force to keep the stone stationary. Thus, the stone will flung away when the rotation is stopped
