Answer:
a) 3.162 m
b) 339.7 W
Explanation:
Assume ρ = 1.50*10^-6 Ωm, and
α = 4.000 10-4(°C)−1 for Nichrome
To solve this, we would use the formula
P = V² / R
So when we rearrange and make R subject of formula, we have
R = V² / P
Resistance of the heating coil, R
R = (110² / 500)
R = 12100 / 500
R = 24.2 ohms
Recall the formula for resistivity of a wire
R = ρ.L/A
Again, in rearranging and making L subject of formula, we have
L = R.A / ρ
To make it uniform, we convert our radius from mm to m.
Diameter, D = 0.5 mm
Radius of wire = 0.5 / 2 mm = 0.25 mm = 0.00025 m
We then use this radius to find our area
A = πr²
A = π * 0.00025²
A = 1.96*10^-7 m²
And finally, we solve for L
L = (24.2 * 1.96*10^-7 / 1.50*10^-6) =
L = 3.162 m
(b)
Temperature coefficient of resistance.
R₁₂₀₀ = R₂₀[1 + α(1200 - 20.0) ]
R₁₂₀₀ = R₂₀[1 + α(1180) ]
R₁₂₀₀ = 24.2[ 1 + 4.*10^-4 * 1180 ]
R₁₂₀₀ = 24.2[1 + 0.472]
R₁₂₀₀ = 24.2 * 1.472
R₁₂₀₀ = 35.62 ohms
Putting this value of R in the first formula from part a, we have
P = V² / R
P = (110² / 35.62)
P = 12100/ 35.62
P = 339.70 watts
(a) Length of the wire is 3.162 m
(b) Power delivered to the coil is 339.7 W
Electrical Power:The electrical power is given by
P = V² / R
R = V² / P
Resistance of the heating coil, R
R = (110² / 500)
R = 12100 / 500
R = 24.2 Ω
Now the resistivity of a wire is given by
ρ= RA/L
here ρ = 1.50×10⁻⁶ Ωm
so after rearranging we get:
L = RA / ρ
Now, the radius of wire r = 0.5 / 2 mm = 0.25 mm = 2.5×10⁻⁴ m
So the cross sectional area can be calculated as follows
[tex]A = \pi r^2\\\\A = \pi \times (2.5\times10^{-4})^2\\\\A = 1.96\times10^{-7} m^2[/tex]
hence,
[tex]L = (24.2 \times1.96\times10^{-7} / 1.50\times10^{-6}) \\\\L = 3.162\; m[/tex]
(b)The dependency of resistance with temperature is as follows:
R = R₀[1 + αΔT]
α = [tex]4\times10^{-4}^\;oC^{-1}[/tex] for Nichrome
[tex]R' = R [1 + \alpha (1200 - 20) ]\\\\R' = R[1 + \alpha (1180) ]\\\\R' = 24.2[ 1 + 4*10^{-4} * 1180 ]\\\\R' = 24.2[1 + 0.472]\\\\R' = 24.2 * 1.472\\\\R' = 35.62 \;\Omega[/tex]
So the power generated is :
P = V² / R
P = (110² / 35.62)
P = 12100/ 35.62
P = 339.70 watts
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A motor requires 400 joules of energy to lift a 5.0 kg mass 2.0 meters. Calculate the efficiency of this motor.
Answer:
25%
Explanation:
use F=mg
then use the answer you get from that and plug it into W=Fxh
take that answer and divide it by 400 J and multiply by 100
round to sig figs
What is the relationship between the focal length of a cylindrical mirror and its radius of curvature?
Answer:
Explanation:
Focal length (f) can be defined as the distance from the focal point to the centre of the surface of the mirror.
While radius of curvature (r) is the radius of the sphere of which the mirror forms a part.
Hence the relationship between the two is that the focal length is half of the length of the radius of curvature.
Mathematically,
F = r/2
Can any answer this plzz
Answer: u failed both sad welp ill try to help
Explanation:
Which best describes most covalent compounds? resilient brittle cold warm
Answer:
B) brittle
Explanation:
This describes most covalent compounds.
Answer:
B.)
Explanation:
The atoms can be of the same element or different elements. In each molecule, the bonds between the atoms are strong but the bonds between molecules are usually weak. This makes many solid materials with covalent bonds brittle.
explain the flow of energy needed to bring electrical energy to the city
Three elements are required to create an electric current: a supply of freely flowing electric charges (electrons), some kind of push to move the charges across the circuit, and a path to carry the charges.
What is Electrical energy?Electrical energy is a type of energy that is related to forces on electrically charged particles and electrically charged particle motion (often electrons in wires, but not always). Electric current and electric potential, which is also known as voltage because it is measured in volts, are delivered via an electrical circuit to provide this energy.
When charged particles and a voltage difference combine, as in static electricity or a charged capacitor, motion (current) is not necessary. Instead, the moving electrical energy is often transformed into another kind of energy.
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A 2.00-m rod of negligible mass connects two very small objects at its ends. The mass of one object is 1.00 kg and the mass of the other is unknown. The center of mass of this system is on the rod a distance 1.60 m from the 1.00-kg mass object. What is the mass of the other object?A) 0.250kg B) 4.00kg C) 4.11kg D) 0.800kg E) 3.22kg
Answer:
4kgExplanation:
Step one:
given
length of rod=2m
mass of object 1 m1=1kg
let the unknown mass be x
center of mass c.m= 1.6m
hence 1kg is 1.6m from the c.m
and x is 0.4m from the c.m
Taking moment about the c.m
clockwise moment equals anticlockwise moments
1*1.6=x*0.4
1.6=0.4x
divide both sides by 0.4 we have
x=1.6/0.4
x=4kg
The mass of the other object is 4kg
a car accelerates from rest to a speed of 36 km/hour in 10 seconds. find
the acceleration
the distance travelled
the speed at the end of the 5th second
Answer: ok, so there should be no speed at the 5th second but there was somehow it was the car fault
∞ω∞
Why are scientists choosing to colonize Mars rather than another planet?
Scientists are choosing to colonize Mars rather than another planet out of curiosity, the potential for humans to provide more in-depth observational research than uncrewed rovers, economic interest in its resources, and the possibility that the settlement of other planets could decrease the likelihood of human extinction.
What is colonization of mars?Colonization requires the establishment of permanent habitats that have the potential for self-expansion and self-sustenance.
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An object is thrown with a horizontal velocity of 49mt/sec and a vertical velocity of 18.8 mt/sec. How long will the object take to return to earth. Please help asap
Answer:
The object takes 3.84 seconds to return to earth.
Explanation:
Projectile Motion
It's when an object projected above the ground at a certain velocity, moves along a curved path under the action of gravity.
The initial velocity has two components, given by:
[tex]v_x=vo_x[/tex]
[tex]v_y=vo_y-gt[/tex]
Where vox is the initial component of the velocity in the horizontal direction, voy is the initial component of the velocity in the vertical direction, and t is the time.
The object reaches a maximum height and then it returns to the ground. The time it takes to reach the maximum height can be calculated when the vertical component of the velocity is zero:
[tex]vo_y-gt=0[/tex]
[tex]\displaystyle t_m=\frac{vo_y}{g}[/tex]
The initial vertical component of the velocity is 18.8 m/s, thus:
[tex]\displaystyle t_m=\frac{18.8}{9.8}=1.92~s[/tex]
The total time is double that time:
[tex]t_t=2*1.92~s=3.84~s[/tex]
The object takes 3.84 seconds to return to earth.
*
Which of the following cannot be an example of projectile motion
A. A football flying through the air
B. An apple falling from a tree
C. A pencil rolling on the ground
D.A rocket dropping from its maximum height
If a feather and an iron bar were fired at the same height in a room without any air resistance, which would fall first and why?
Which best describes the surface of a concave mirror?
O It is flat.
0 It is textured.
Olt curves outward.
0 It curves inward.
Answer:
It curves inward
Explanation:
Of the choices given it is the only one that makes sense
Considering the concave mirror to be a part of a large sphere and the outer surface polished, we can say it curves inward.
Concave mirror:There are three types of mirrors: plain mirrors, convex mirrors, and concave mirrors.
The plain mirrors are the ones which we use in our houses. It has both the sides flat, front and back. With the back end polished to reflect light.
It is obvious that the back end of the mirror must be silvered or polished in order to reflect light.
In the case of concave mirrors, if we consider it a part of a large sphere, then the outer surface is silvered or polished and the inner surface is the surface that is used as a mirror,
So, we can say that a concave mirror curves inward.
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plzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz help meeeeeeeeeeeeeeeeeeeeeee 15 points
Answer:
ALUMINUM ITS ALUMINUM BRO
Explanation:
What is the frequency of an xray with a wavelength of 2x10-10m?
a) 1.5x1018hz
b) 6.67x10-19hz
c) 3x108hz
d) 1.5hz
Show calculation
Answer:
1.5 x 10¹⁸hz
Explanation:
Given parameters:
Wavelength = 2 x 10⁻¹⁰m
Unknown:
Frequency = ?
Solution:
To find the frequency, use the expression below;
V = f x wavelength
V is the speed of light = 3 x 10⁸m/s
f is the frequency
Now;
Insert the parameters
3 x 10⁸ = 2 x 10⁻¹⁰ x frequency
Wavelength = [tex]\frac{3 x 10^{8} }{2 x 10^{-10} }[/tex] = 1.5 x 10¹⁸hz
a. Some materials exhibit the property of superconductivity under certain conditions.
State what is meant by superconductivity and explain the required conditions for the
material to become superconducting.
Answer:
Conditions for Superconductivity
The material must be cooled below a characteristic temperature, known as its superconducting transition or critical temperature (Tc). ... The magnetic field to which the material is exposed must be below a characteristic value known as the critical magnetic field (Hc).
A 0.10 g flea, having leapt from the surface of a dog’s cranium, is observed to be moving at 1.25 m/s when it is 5.00 cm above the position from which it leapt. What was the elastic potential energy stored in its legs before its leap
Answer:
E.P.E = 1.27 x 10⁻⁴ J = 0.127 mJ
Explanation:
From Law of Conservation Energy, we know that:
Elastic Potential Energy Stored = Gain in Kinetic Energy + Gain in Gravitational Potential Energy
E.P.E = (1/2)mv² + mgh
where,
E.P.E = Elastic Potential Energy = ?
m = mass of flea = 0.1 g = 1 x 10⁻⁴ kg
v = speed = 1.25 m/s
g = 9.8 m/s²
h = height = 5 cm = 0.05 m
Therefore,
E.P.E = (1/2)(1 x 10⁻⁴ kg)(1.25 m/s)² + (1 x 10⁻⁴ kg)(9.8 m/s²)(0.05 m)
E.P.E = 0.78 x 10⁻⁴ J + 0.49 x 10⁻⁴ J
E.P.E = 1.27 x 10⁻⁴ J = 0.127 mJ
5) True or False: Inertia is the ability for an object to keep its motion
O True
O False
Answer:
true
Explanation:
What is the purpose of using an ammeter to demonstrate that a moving
magnet causes an electric current to flow in a wire coil?
A. It detects any current in the wire.
B. It protects the investigators from receiving an electric shock.
C. It increases the strength of the permanent magnet.
D. It takes the place of the battery needed for an electromagnet.
Answer: A
Explanation:
Answer:
The answer is A. It detects any current in the wire.
Explanation:
I took the quiz.
What statement best describes how wind weathered this rock
The rock slowly moved over time due to the force of the wind.
The shape of the rock changed when the pressure of wind increased.
The rock broke down when the wind blew particles of sand against it.
The rock broke down when the temperature in the air decreased.
Answer:
the rock breaks down when the wind blows particles of sand against it.
Explanation:
because the sand can easily be decomposed and temperature easily accessible to it cause line of weaknesses of the rock to break down
How does the velocity of a falling object change with time? How would you describe the mathematical relationship between velocity and time of a falling object?
Answer:
Increases with time via the relationship:
velocity = acceleration * time = g * t
Explanation:
Since the object is falling under the constant acceleration due to gravity, its velocity is increasing with time. Such relationship can be described via the equation:
velocity = acceleration * time = g * t
Where the direction of the acceleration due to gravity (g) (pointing downwards) is in the same direction of that of the object's velocity.
Consider a cylindrical pipe with both ends open and fundamental resonance frequency 150 Hz. If this particular pipe has a length of L, what the wavelengths of three lowest modes produced by this pipe? Select an answer and submit. For keyboard navigation, use the up/down arrow keys to select an answer. a. L,2L, 3L b. 2L, L, 2L/3 с. 2L/3, L, 2L d. L, L/2, L/3 e. 4L, 24, 4L/3 f. 4L, 4L/3, 4L/5 g. Neither of above.
Answer:
answers, the correct one is b
Explanation:
For this problem we use the fact that since the ends are open at these points we have a maximum,
fundamental L =λ/2 λ = 2L
second harmonic L = λ λ = 2L / 2
third harmonic L = 3 λ/2 λ = 2L / 3
n harmonic lam = 2L / n
with n an integer
therefore the length of the first three harmonics are: 2L, L, 2L / 3
when examining the different answers, the correct one is b
Sara goes to her apartment on the fifth floor by elevator from
the ground floor. The whole journey is 18.0 meters. If Sara hasmass 60 kg, what is the gravitational potential energy gained
by her? Estimate gas 9.81m/s2.
Answer: 10595 J
Explanation: cK-12 Potential Energy
The gravitational potential energy gained by Sara if she has a mass of 60 kg and the distance of the journey is 18 meters is 10584 Joules.
What is gravitational potential energy?The potential energy that a huge item has in relation to another massive object due to gravity is known as gravitational energy or gravitational potential energy. When two objects descend toward one another, the potential energy associated with the gravitational field is released (transformed into kinetic energy). Bringing two things farther apart increases the gravitational potential energy.
Given:
The distance of the journey, d = 18 meters,
The mass of Sara, m = 60 kg,
Calculate the potential energy by the following formula,
PE = m × g × d
Here, PE is the potential energy and g is gravitational acceleration,
Substitute the values,
PE = 60 × 18 × 9.8
PE = 10584 Joules
Therefore, the gravitational potential energy gained by Sara if she has a mass of 60 kg and the distance of the journey is 18 meters is 10584 joules.
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Given a force of 56 N and an acceleration of 7 m/s2, what is the mass?
Answer:
8 kgExplanation:
The mass of an object can be found by using the formula
[tex]m = \frac{f}{a} \\ [/tex]
f is the force
a is the acceleration
From the question we have
[tex]m = \frac{56}{7} \\ [/tex]
We have the final answer as
8 kgHope this helps you
Answer:
8 kg*m/s (8 kg)
Explanation:
f= 56 N
a= 7 m/s^2
m= ?
m= 56 N / 7 m/s^2
= 8 kg*m/s
(8 kg)
The intensity of a sound wave at a fixed distance from a speaker vibrating at 1.00 kHz is 0.750 W/m2. (a) Determine the intensity if the frequency is increased to 2.20 kHz while a constant displacement amplitude is maintained.(b) Calculate the intensity if the frequency is reduced to 0.250 kHz and the displacement amplitude is quadrupled.
Answer:
a) I = 3.63 W / m² , b) I = 0.750 W / m²
Explanation:
The intensity of a sound wave is given by the relation
I = P / A = ½ ρ v (2π f [tex]s_{max}[/tex])²
I = (½ ρ v 4π² s_{max}²) f²
a) with the initial condition let's call the intensity Io
cte = (½ ρ v 4π² s_{max}²)
I₀ = cte s² f₀²
I₀ = cte 10 6
If frequency is increase f = 2.20 10³ Hz
I = constant (2.20 10³) 2
I = cte 4.84 10⁶
let's find the relationship of the two quantities
I / Io = 4.84
I = 4.84 Io
I = 4.84 0.750
I = 3.63 W / m²
b) in this case the frequency is reduced to f = 0.250 10³ Hz and the displacement s = 4 s or
I = cte (f s)²
I = constant (0.250 10³ 4)²
I = cte 1 10⁶
the relationship
I / Io = 1
I = Io
I = 0.750 W / m²
A 25 kg of bananas is being pushed across the floor with a force of 37.5 N. What is the acceleration of the crate?
What is the force acting an object that is accelerating at 3.6 m/s/s and has a mass of 15 kg?
Answer:
54 NExplanation:
The force acting on an object given it's mass and acceleration can be found by using the formula
force = mass × acceleration
From the question we have
force = 15 × 3.6
We have the final answer as
54 NHope this helps you
Imagine that you are approaching a black hole in a spacecraft. What would you see? What would happen to you?
(please a short simple answer if possible)
A 15-cm-diameter CD has a mass of 25 g.A. What is the CD's moment of inertia for rotation about a perpendicular axis through its center?B. What is the CD's moment of inertia for rotation about a perpendicular axis through the edge of the disk?
Solution :
The moment of inertia for a circular disc about its centre is given by
[tex]$I=\frac{mr^2}{2}$[/tex]
Given , radius of CD, [tex]$r=\frac{d}{2}$[/tex]
[tex]$r=\frac{1.5 \times 10^{-2}}{2}$[/tex]
[tex]$=7.5 \times 10^{-2} \ m$[/tex]
A).
The moment of inertia of CD about its centre is
[tex]$I_{centre}=\frac{mr^2}{2}$[/tex]
[tex]$=\frac{25 \times 10^{-3}\times (7.5 \times 10^{-2})^2}{2}$[/tex]
[tex]$= 7\times 10^{-5} \ kg \ m^2$[/tex]
B).
The moment of inertia about parallel axis of CD with respect to its central axis is given by the parallel axis theorem,
[tex]$I_{p}=I_c + md^2$[/tex]
where, d is the distance between the parallel axis and central axis
Therefore, moment of inertia of CD about its edge is
[tex]$I_p=I_c +md^2$[/tex]
[tex]$=\frac{mr^2}{2}+mr^2$[/tex]
[tex]$=\frac{3}{2}mr^2$[/tex]
[tex]$=\frac{3(25 \times 10^{-3})\times (7.5 \times 10^{-2})^2}{2}$[/tex]
[tex]$=2.1 \times 10^{-4} \ kg \ m^2$[/tex]
(a) The CD's moment of inertia for rotation about a perpendicular axis through its center is [tex]7.031 \times 10^{-5} \ kgm^2[/tex]
(b) The CD's moment of inertia for rotation about a perpendicular axis through the edge of the disk is [tex]2.11 \times 10^{-4} \ kgm^2[/tex]
The given parameters;
diameter of the CD, d = 15 cmradius of the CD, r = 7.5 cmmass of the CD, m = 25 g = 0.025 kg(A) The CD's moment of inertia for rotation about a perpendicular axis through its center is calculated as follows;
[tex]I_c = \frac{1}{2} mr^2\\\\I_c = \frac{1}{2} \times 0.025 \times (0.075)^2\\\\I_c = 7.03 1 \times 10^{-5} \ kgm^2[/tex]
(B) The CD's moment of inertia for rotation about a perpendicular axis through the edge of the disk is calculated as;
[tex]I_p = I_c + mr^2\\\\I_p = (7.031 \times 10^{-5}) \ + \ 0.025 \times (0.075)^2\\\\I_p = 2.11 \times 10^{-4} \ kgm^2[/tex]
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A wave has a frequency of 15,500 Hz and a wavelength of 0.20 m. What is the
speed of the wave? Use the equation v=fx2.
A. 0.0000013 m/s
B. 3100 m/s
O C. 78,000 m/s
D. 0.00032 m/s
Answer:
it's B for a pe x
Explanation:
A 45 N brick is suspended by a light string over a 2.0 kg pulley. Initially, the pulley is prevented from rotating. The pulley is then released from rest. What is the angular speed of the pulley at the instant it has rotated through 5 radians. The pulley may be considered a solid disk of radius 1.5 m. What is the angular speed of the pulley? I know the answer is 7.33 rad/s but i need to know how they got to this answer.
Answer: 17.3rad/secs.
Explanation:
Given data:
m = 2.0kg
f = 45N
radius of the disk = 1.5m
Solution:
First we determine the kinetic energy of the the system
= 1/2jw^2 + 1/2m(wR)^2
when the brick falls at wR m/s
= 1/2( j + mR^2)w^2
= 1/2 (1/2MR^2 + mR^2)w^2
Loss in potential energy when the brick drops
= 5rad * 1.5m
= 7.5m
Therefore;
45N * 7.5m = 1/2Iw^2
where;
I = 1/2mr^2
angular speed
w = √4*45*7.5/(2*1.5^2)
= 17.3rad/secs
