Answer:
One can write F = K d^-2 where K = G M m
So dF/dd = -2 K d^-3 = -2 K / d^3 (As d increases F decreases - it is opposite to the direction of F)
What is the current in milliamperes produced by the solar cells of a pocket calculator through which 9.00 C of charge passes in 8.50 h
Answer:
Current = 0.000294 A
Explanation:
Below is the given values:
Given the charge = 9.00 C
Time = 8.50 h
Use the below formula to find the current:
Current = Q / t
Now plug the values:
Current = 9 / (8.5 x 3600)
Current = 0.000294 A
Which has a total mass of 1612 kg. If she accelerates from rest to a speed of 12.87 m/s in 3.47 s, what is the minimum power required of the engine?
Answer:
76969.29 W
Explanation:
Applying,
P = F×v............. Equation 1
Where P = Power, F = force, v = velocity
But,
F = ma.......... Equation 2
Where m = mass, a = acceleration
Also,
a = (v-u)/t......... Equation 3
Given: u = 0 m/s ( from rest), v = 12.87 m/s, t = 3.47 s
Substitute these values into equation 3
a = (12.87-0)/3.47
a = 3.71 m/s²
Also Given: m = 1612 kg
Substitute into equation 2
F = 1612(3.71)
F = 5980.52 N.
Finally,
Substitute into equation 1
P = 5980.52×12.87
P = 76969.29 W
An initially motionless test car is accelerated uniformly to 105 km/h in 8.43 s before striking a simulated deer. The car is in contact with the faux fawn for 0.635 s, after which the car is measured to be traveling at 60.0 km/h. What is the magnitude of the acceleration of the car before the collision?
acceleration before collision:
3.45
m/s2
What is the magnitude of the average acceleration of the car during the collision?
average acceleration during collision:
19.68
m/s2
What is the magnitude of the average acceleration of the car during the entire test, from when the car first begins moving until the collision is over?
105 km/h ≈ 29.2 m/s
60.0 km/h ≈ 16.7 m/s
Before the collision the test car has an acceleration a of
a = (29.2 m/s - 0) / (8.43 s) ≈ 3.46 m/s²
During the collision, the car is slowed to about 16.7 m/s, so that its (average) acceleration is
a = (16.7 m/s - 29.2 m/s) / (0.635 s) ≈ -19.7 m/s²
i.e. with magnitude about 19.7 m/s².
Overall, the car has an average acceleration of
a = (16.7 m/s - 0) / (8.43 s + 0.635 s) ≈ 1.84 m/s²
A glass block in air has critical angle of 49. What will happen to a ray of light coming through the glass when it is incident at and angle of 50 at the glass air boundary? Illustrate with a diagram
Answer:
b
Explanation:
The blades of a fan running at low speed turn at 26.2 rad/s. When the fan is switched to high speed, the rotation rate increases uniformly to 36.5 rad/s in 5.75 seconds. What is the magnitude of the fan's angular acceleration
Answer: [tex]1.79\ rad/s^2[/tex]
Explanation:
Given
Initial angular speed is [tex]\omega_1=26.2\ rad/s[/tex]
Final angular speed is [tex]\omega_2=36.5\ rad/s[/tex]
Time period [tex]t=5.75\ s[/tex]
Magnitude of the fan's acceleration is given by
[tex]\Rightarrow \alpha=\dfrac{\omega_2-\omega_1}{t}[/tex]
Insert the values
[tex]\Rightarrow \alpha=\dfrac{36.5-26.2}{5.75}\\\\\Rightarrow \alpha=\dfrac{10.3}{5.75}\\\\\Rightarrow \alpha=1.79\ rad/s^2[/tex]
Thus, fan angular acceleration is [tex]1.79\ rad/s^2[/tex]
Answer:
The angular acceleration is given by 1.8 rad/s^2.
Explanation:
initial angular speed, wo = 26.2 rad/s
final angular velocity, w = 36.5 rad/s
time, t = 5.75 seconds
The first equation of motion is
[tex]w = wo + \alpha t\\\\36.5 = 26.2 + 5.75\alpha\\\\\alpha = 1.8 rad/s^2[/tex]
A 900 kg car travelling at 12 m/s due east collides with a 600 kg car travelling at 24 m/s due north. As a result of the collision, the two cars lock together and move in what final direction?
45.0° N of E
53.1° N of E
63.3° N of E
69.5° N of E
Calculate force of each car:
P1 = 900 kg x 12m/s = 10,800
P2= 600 x 24 = 14,400
Degree of travel = arctan(14,300/10800)
Degree of travel = 53.1 N of E
A 61.1-kg person, running horizontally with a velocity of +2.16 m/s, jumps onto a 16.1-kg sled that is initially at rest. (a) Ignoring the effects of friction during the collision, find the velocity of the sled and person as they move away. (b) The sled and person coast 30.0 m on level snow before coming to rest. What is the coefficient of kinetic friction between the sled and the snow?
Answer:
(a) v = 1.71 m/s
(b) μ = 0.005
Explanation:
(a)
Using the law of conservation of the momentum:
[tex]m_1u_1+m_2u_2=m_1v_1+m_2v_2\\[/tex]
where,
m₁ = mass of person = 61.1 kg
m₂ = mass of sled = 16.1 kg
u₁ = initial speed of the person = 2.16 m/s
u₂ = initial speed of the sled = 0 m/s
v₁ = v₂ = v = final speeds of both the person and the sled = ?
Therefore,
[tex](61.1\ kg)(2.16\ m/s)+(16.1\ kg)(0\ m/s)=(61.1\ kg)(v)+(16.1\ kg)(v)\\\\v = \frac{131.976\ kgm/s}{77.2\ kg}[/tex]
v = 1.71 m/s
(b)
The kinetic energy lost by the sled must be equal to the frictional energy:
K.E = fd
[tex]\frac{1}{2}mv^2=\mu Rd = \mu Wd\\\\\frac{1}{2}mv^2=\mu mgd\\\\\frac{1}{2}v^2=\mu g\\\\\mu = \frac{v^2}{2gd}[/tex]
where,
μ = coefficient of kinetic friction = ?
d = distance covered = 30 m
g = acceleration due to gravity = 9.81 m/s²
Therefore,
[tex]\mu = \frac{(1.71\ m/s)^2}{(2)(9.81\ m/s^2)(30\ m)}[/tex]
μ = 0.005
An eagle is flying horizontally at a speed of 2.60 m/s when the fish in her talons wiggles loose and falls into the lake 4.70 m below. Calculate the velocity (in m/s) of the fish just before it hits the water. (Assume that the eagle is flying in the x direction and that the y direction is up.)
Answer:
Explanation:
The fish will have horizontal velocity of 2.6 m/s which is also the velocity of eagle. Additionally , he will have vertical velocity due to fall under gravity .
v² = u² + 2 g H .
v² = 0 + 2 x 9.8 x 4.7 m
= 92.12
v = 9.6 m /s
The fish's final velocity will have two components
vertical component = 9.6 m/s downwards
Horizontal component = 2.6 m /s .
Resultant velocity = √ ( 9.6² + 2.6² )
= √ ( 92.16 + 6.76 )
= 9.9 m /s
Answer:
The speed of fish at the time of hitting the surface is 9.95 m/s.
Explanation:
Horizontal speed, u = 2.6 m/s
height, h = 4.7 m
Let the vertical velocity at the time of hitting to water is v.
Use third equation of motion
[tex]v^2 = u^2 - 2 gh \\\\v^2 = 0 + 2 \times 9.8\times 4.7\\\\v = 9.6 m/s[/tex]
The net velocity with which the fish strikes to the water is
[tex]v' = \sqrt{9.6^2 + 2.6^2 }\\\\v' = 9.95 m/s[/tex]
A tall cylinder contains 25 cm of water. Oil is carefully poured into the cylinder, where it floats on top of the water, until the total liquid depth is 40 cm. What is the gauge pressure at the bottom of the cylinder
Answer: [tex]377.3\ kPa[/tex]
Explanation:
Given
Water column height [tex]h=25\ cm[/tex]
After oil is poured, the total height becomes [tex]h'=40\ cm[/tex]
Pressure at the bottom will be the sum due to the water and oil column
Suppose the density of the oil is [tex]\rho=900\ kg/m^3[/tex]
Pressure at the bottom
[tex]\Rightarrow P=10^3\times g\times 25+900\times g\times 15\\\Rightarrow P=100g[250+135]\\\Rightarrow P=3773\times 100\ Pa\\\Rightarrow P=377.3\ kPa[/tex]
Consider an electromagnetic wave propagating through a region of empty space. How is the energy density of the wave partitioned between the electric and magnetic fields?
1. The energy density of an electromagnetic wave is 25% in the magnetic field and 75% in the electric field.
2. The energy density of an electromagnetic wave is equally divided between the magnetic and electric fields.
3. The energy density of an electromagnetic wave is entirely in the magnetic field.
4. The energy density of an electromagnetic wave is 25% in the electric field and 75% in the magnetic field.
5. The energy density of an electromagnetic wave is entirely in the electric field
Answer:
Option (2) is correct.
The energy density of an electromagnetic wave is equally divided between the magnetic and electric fields.
Explanation:
An electromagnetic waves are the waves which are produced when the oscillating electric and magnetic field are interact each other perpendicular to each other. The direction of propagation of electro magnetic waves is perpendicular to each electric and magnetic fields.
The energy associated with the electromagnetic waves is equally distributed in form of electric and magnetic fields.
So, the correct option is (2).
The energy density is equally distributed among the magnetic field and electric field. Hence, option (2) is correct.
The given problem is based on the concept and fundamentals of electromagnetic waves. The waves created as a result of vibrations between an electric field and a magnetic field is known as Electromagnetic waves.
In other words, an electromagnetic waves are the waves which are produced when the oscillating electric and magnetic field are interact each other perpendicular to each other. The direction of propagation of electro magnetic waves is perpendicular to each electric and magnetic fields.
Also, the energy associated with the electromagnetic waves is equally distributed in form of electric and magnetic fields. So, the energy density of an electromagnetic wave is equally divided between the magnetic and electric fields.
Thus, we can conclude that the energy density is equally distributed among the magnetic field and electric field.
Learn more about the electromagnetic waves here:
https://brainly.com/question/25559554
pha của dao động làm hàm
Answer:
pha của dao động là hàm bậc nhất của thời gian.
Reflected waves change their wavelength by ______ when reflected.
A. ¾
B. ½
C. They don’t change
D. ¼
Answer:
i think its c
Explanation:
trust me
A playground merry-go-round has a mass of 120 kg and a radius of 1.80 m and it is rotating with an angular velocity of 0.500 rev/s. What is its angular velocity after a 22.0-kg child gets onto it by grabbing its outer edge
Answer:
I think it is of science is it true na i knew it bro dont take tension
To get maximum current in a circuit, the resistance should be in _____
1)series
2)parallel
Answer:
no parallel is the correct answer
A 1.5m long string weighs 0.0020 kg. It is tensioned to 100N. A disturbance travels along it with a wavelength of 1.5m, find:a) the propagation velocity of the wave
Answer:
the propagation velocity of the wave is 274.2 m/s
Explanation:
Given;
length of the string, L = 1.5 m
mass of the string, m = 0.002 kg
Tension of the string, T = 100 N
wavelength, λ = 1.5 m
The propagation velocity of the wave is calculated as;
[tex]v = \sqrt{\frac{T}{\mu} } \\\\\mu \ is \ mass \ per \ unit \ length \ of \ the \ string\\\\\mu = \frac{0.002 \ kg}{1.5 \ m} = 0.00133 \ kg/m\\\\v = \sqrt{\frac{100}{0.00133} } \\\\v = 274.2 \ m/s[/tex]
Therefore, the propagation velocity of the wave is 274.2 m/s
A measurement was made of the magnetic field due to a tornado, and the result was 13.00 nT to the north. The measurement was made at a position 8.90 km west of the tornado. What was the magnitude (in A) and direction of the current in the funnel of the tornado? Assume the vortex was a long, straight wire carrying a current.
Answer:
4
Explanation:
The index of refraction for a vacuum is 1.00000. The index of refraction for air is 1.00029. 1) Determine the ratio of time required for light to travel through 1000 m of air to the time required for light to travel through 1000 m of vacuum. (Express your answer to six significant figures.)
Answer:
[tex]\frac{t_{air}}{t_{vaccum}}[/tex] = 1.00029
Explanation:
The refractive index is defined
n = c / v
v = c / n
the speed of light per se wave is constant, so we can use the relations of uniform motion
v = x / t
t = x / v
we substitute
t = x n / c
let's calculate the time
vacuum
t₁ = 1000 1/3 10⁸
t₁ = 3.333333 10⁻⁶ s
air
t₂ = 1000 1.00029 / 3 10⁸
t2 = 3.3343 10⁻⁶ s
the relationship between these times is
t₂ / t₁ = 3.3343 / 3.3333333
t₂ / t₁ = 1.00029
Two resistors with resistance values of 4.5 Ω and 2.3 Ω are connected in series or parallel
across a 30 V potential difference to a light bulb.
a. Calculate the current delivered through the light bulb in the two cases.
b. Draw the circuit connection that will achieve the brightest light bulb.
Explanation:
Given that,
Two resistors 4.5 Ω and 2.3 Ω .
Potential difference = 30 V
When they are in series, the current through each resistor remains the same. First find the equivalent resistance.
R' = 4.5 + 2.3
= 6.8 Ω
Current,
[tex]I=\dfrac{V}{R'}\\\\I=\dfrac{30}{6.8}\\\\=4.41\ A[/tex]
So, the current through both lightbulb is the same i.e. 4.41 A.
When they are in parallel, the current divides.
Current flowing in 4.5 resistor,
[tex]I_1=\dfrac{V}{R_1}\\\\=\dfrac{30}{4.5}\\\\I_1=6.7\ A[/tex]
Current flowing in 2.3 ohm resistor,
[tex]I_2=\dfrac{V}{R_2}\\\\=\dfrac{30}{2.3}\\\\I_2=13.04[/tex]
In parallel combination, are brighter than bulbs in series.
Power selection feature for resistors to become water modules 10 liters of water at 25°C to đến
95oC for 20 minutes.
Answer:
P = 2439.5 W = 2.439 KW
Explanation:
First, we will find the mass of the water:
Mass = (Density)(Volume)
Mass = m = (1 kg/L)(10 L)
m = 10 kg
Now, we will find the energy required to heat the water between given temperature limits:
E = mCΔT
where,
E = energy = ?
C = specific heat capacity of water = 4182 J/kg.°C
ΔT = change in temperature = 95°C - 25°C = 70°C
Therefore,
E = (10 kg)(4182 J/kg.°C)(70°C)
E = 2.927 x 10⁶ J
Now, the power required will be:
[tex]Power = P = \frac{E}{t}[/tex]
where,
t = time = (20 min)(60 s/1 min) = 1200 s
Therefore,
[tex]P = \frac{2.927\ x\ 10^6\ J}{1200\ s}[/tex]
P = 2439.5 W = 2.439 KW
A cube, whose edges are aligned with the , and axes, has a side length . The field is immersed in an electric field aligned with the axis. On the left and right faces, the field has a strength and , respectively. The field along the front and back faces has strengths and . The field at the bottom and top faces has strengths and , respectively. What is the total charge enclosed by the cube
Complete Question
Complete Question is attached below
Answer:
[tex]q=1.558*10^{-9}c[/tex]
Explanation:
From the question we are told that:
Side length s=1.13m
Left field strength [tex]E_l=784.75N/m[/tex]
Right field strength [tex]E_r=776.38 N/m[/tex]
Front field strength [tex]E_f=725.5 N/m[/tex]
Back field strength [tex]E_b=749.54 N/m[/tex]
Top field strength [tex]E_t=944.95 N/m[/tex]
Bottom field strength [tex]E_{bo}=1082.58 N/m[/tex]
Generally, the equation for Charge flux is mathematically given by
[tex]\phi=EAcos\theta[/tex]
Where
Theta for Right,Left,Front and Back are at an angle 90
[tex]cos 90=0[/tex]
Therefore
[tex]\phi =0[/tex] with respect to Right,Left,Front and Back
Generally, the equation for Charge Flux is mathematically also given by
[tex]\phi=\frac{q}{e_o}[/tex]
Where
[tex]Area =L*B\\\\A=1.13*1.13\\\\A=1.2769m^2[/tex]
Therefore
[tex]Q_{net}=E_{bo}Acos\theta_{bo} +E_tAcos\theta_t[/tex]
[tex]Q_{net}=1082.85*1.2769*cos0=944.95*1.2769cos (180)[/tex]
[tex]Q_{net}=176N/C m^2[/tex]
Giving
[tex]q=\phi*e_0[/tex]
[tex]q=176N/C m^2*1.558*10^{-12}c[/tex]
[tex]q=1.558*10^{-9}c[/tex]
The initial height of the water in a sealed container of diameter 100.0 cm is 5.00 m. The air pressure inside the container is 0.850 ATM. A faucet with an opening 1.0 inch diameter is located at the bottom of the container.
Required:
a. What is the net force on the side of the container?
b. How long does it take and how much the water level will drop till water no longer comes out of the faucet?
Answer:
a) F = 2.66 10⁴ N, b) h = 1.55 m
Explanation:
For this fluid exercise we use that the pressure at the tap point is
Exterior
P₂ = P₀ = 1.01 105 Pa
inside
P₁ = P₀ + ρ g h
the liquid is water with a density of ρ=1000 km / m³
P₁ = 0.85 1.01 10⁵ + 1000 9.8 5
P₁ = 85850 + 49000
P₁ = 1.3485 10⁵ Pa
the net force is
ΔP = P₁- P₂
Δp = 1.3485 10⁵ - 1.01 10⁵
ΔP = 3.385 10⁴ Pa
Let's use the definition of pressure
P = Fe / A
F = P A
the area of a circle is
A = pi r² = [i d ^ 2/4
let's reduce the units to the SI system
d = 100 cm (1 m / 100 cm) = 1 m
F = 3.385 104 pi / 4 (1) ²
F = 2.66 10⁴ N
b) the height for which the pressures are in equilibrium is
P₁ = P₂
0.85 P₀ + ρ g h = P₀
h = [tex]\frac{P_o ( 1-0.850)}{\rho \ g}[/tex]
h = [tex]\frac{1.01 \ 10^5 ( 1 -0.85)}{1000 \ 9.8}[/tex]
h = 1.55 m
20 raindrops fall on an umbrella. The following day, 10 hail stones fall on the umbrella. All drops of rain and hail are of equal mass m and are traveling at the same velocity v. Both of these (rain and hail) fall on the umbrella in 1 second. What can we say about the Force exerted on the umbrella to hold it up
Answer:
the force exerted by the umbrella against the drops is the same in both cases
Explanation:
In this exercise the total mass of the raindrops and the hail are equal, therefore the momentum that these drops create is
raindrops I₁ = ∫ F dt
hail I₂ = ∫ F dt
since the mass and the velocity is the same the force is the weight of the drops
F = mg
whereby the impulse is
I₁ = mg t
I₂ = mg t
we can see that the impulses generated by hail and raindrops are equal, therefore the force exerted by the umbrella against the drops is the same in both cases
Wind instruments like trumpets and saxophones work on the same principle as the "tube closed on one end" that we examined in our last experiment. What effect would it have on the pitch of a saxophone if you take it from inside your house (76 degrees F) to the outside on a cold day when the outside temperature is 45 degrees F?
Answer:
The correct answer is - low pitch
Explanation:
Now for the case it is mentioned that the tube closed on one end frequency is:
f = v/2l
Where,
l = length of the tube
v = velocity of longitudinal wave of gas filled in the tube
if frequency increases then pitch will be increase as well as pitch depends on frequency.
Now increase with the temperature the density of the gas decreases and velocity v is inversely proportional to density of gas so velocity increases. So if there is an increase in frequency so pitch also increases.
As the temperature inside the house is at 750 F more than outsideat 450 Fso pitch is more inside and the pitch is low outside.
Work-Energy Theorem & Power
A 0.5 kg mass sitting on smooth ice is accelerated from rest by a force until is
acquires a speed of 8 m/s. The force acts while the mass moves through a
displacement of 2 m.
A. Calculate the kinetic energy of the mass after the force acts.
B. Calculate the work done by the force.
C. Calculate the magnitude of the force that accelerated the mass.
Answer:
A. 16 J
B. 16 J
C. 8 N
Explanation:
A. Determination of the kinetic energy.
Mass (m) = 0.5 Kg
Velocity (v) =. 8 m/s
Kinetic energy (KE) =?
KE = ½mv²
KE = ½ × 0.5 × 8²
KE = ½ × 0.5 × 64
KE = 0.5 × 32
KE = 16 J
B. Determination of the Workdone by the force.
Kinetic energy (KE) = 16 J
Workdone =.?
Workdone and kinetic energy has the same unit of measurement. Thus,
Workdone = kinetic energy
Workdone = 16 J
C. Determination of the force.
Workdone (Wd) = 16 J
Displacement (s) = 2 m
Force (F) =?
Wd = F × s
16 = F × 2
Divide both side by 2
F = 16 / 2
F = 8 N
NEED AN ANSWER QUICKLY PLEASE!!
If the length and number of turns of a solenoid are doubled strength of magnetic field will :
(a) Be doubled (b) become half (c) not change d) be four time
Answer:
c). It wouldn't change.
Explanation:
[tex]{ \bf{F = \frac{ \ \gamma _{o}NI }{l} }}[/tex]
A 70-turn coil has a diameter of 11 cm. Find the magnitude of the emf induced in the coil (in V) if it is placed in a spatially uniform magnetic field of magnitude 0.70 T so that the face of the coil makes the following angles with the magnetic field, and the magnetic field is reduced to zero uniformly in 0.2 s.
This question is incomplete, the complete question is;
A 70-turn coil has a diameter of 11 cm. Find the magnitude of the emf induced in the coil (in V) if it is placed in a spatially uniform magnetic field of magnitude 0.70 T so that the face of the coil makes the following angles with the magnetic field, and the magnetic field is reduced to zero uniformly in 0.2 s. a) θ = 30° V b) θ = 60° V c) θ = 90° V
Answer:
the magnitude of the emf induced in the coil are;
a)- For θ = 30°, e = 1.16 V
b)- For θ = 60°, e = 2.01 V
c)- For θ = 90°, e = 2.33 V
Explanation:
Given the data in the question;
number of turns N = 70
Diameter of coil D = 11 cm
Radius r = D/2 = 11/2 = 5.5 cm = 0.055 m
magnitude of magnetic ΔB = 0.7T
Δt = 0.2 seconds
Now,
a)
For θ = 30°,
Angle of with area of vector θ' = 90° - 30° = 60°
so
emf e = N( Δ∅ / Δt ) = N( ΔBAcosθ / Δt )
hence
e = NAcosθ'(ΔB / Δt )
where A is area ( πr² )
so we substitute
e = 70 × πr² × cos(60°) × ( 0.7 / 0.2 )
e = 70 × π(0.055)² × cos(60°) × ( 0.7 / 0.2 )
e = 1.16 V
b)
For θ = 60°,
Angle of with area of vector θ' = 90° - 60° = 30°
so
e = NAcosθ'(ΔB / Δt )
we substitute
e = 70 × πr² × cos(30°) × ( 0.7 / 0.2 )
e = 70 × π(0.055)² × cos(30°) × ( 0.7 / 0.2 )
e = 2.01 V
c)
For θ = 90°,
Angle of with area of vector θ' = 90° - 90° = 0°
so
e = NAcosθ'(ΔB / Δt )
we substitute
e = 70 × πr² × cos(0°) × ( 0.7 / 0.2 )
e = 70 × π(0.055)² × cos(30°) × ( 0.7 / 0.2 )
e = 2.33 V
Therefore, the magnitude of the emf induced in the coil are;
a)- For θ = 30°, e = 1.16 V
b)- For θ = 60°, e = 2.01 V
c)- For θ = 90°, e = 2.33 V
The reason why a teacher is more important then a farmer
Answer:
A teacher is more important than a famer.
Explanation:
A teacher is more important than a famer because the knowledge of farming is gotten through the teacher. Thus, without a teacher; whether formal or informal, there cannot be farming, let alone farmers.
An inductor has an inductance of 0.053 H. The voltage across this inductor is 48 V and has a frequency of 270 Hz. What is the current in the inductor?
Answer:
3.004A
Explanation:
The voltage across an inductor is expressed as:
[tex]V=IX_L\\V=I(2\pi fL)[/tex]
Given
f = 270Hz
V = 48V
L =0.053 H
Get the current
270 = I (2*3.14*270*0.053)
270 = 89.8668I
I = 270/89.8668
I = 3.004A
Hence the current in the inductor is 3.004A
Question 15
Calculate the velocity of a body if its total energy is three times its rest energy
OA 0.54c
OB. 0.760
OC0.94c
OD.C
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A certain heating element is made out of Nichrome wire and used with the standard voltage source of V=120 V. Immediately after the voltage is turned on, the current running through the element is measured at I1=1.28 A and its temperature at T1=25°C. As the heating element warms up and reaches its steady-state (operating) temperature, the current becomes I2=1.229 A.
Required:
Find this steady-state temperature T2.
Answer:
T₁ = 232.5 ºC
Explanation:
For this exercise let's start by finding the value of the resistance for the two currents, using Ohm's law
V = i R
R = V / i
i₀ = 1.28 A
R₀ = 120 / 1.28
R₀ = 93.75 ohm
i₁ = 1.229 A
R₁ = 120 / 1.229
R₁ = 97.64 or
Resistance in a metal is linear with temperature
ΔR = α R₀ ΔT
where the coefficient of thermal expansion for Nichrome is α=0.0002 C⁻¹
ΔT = [tex]\frac{\Delta R}{\alpha R_o}[/tex]
ΔT = [tex]\frac{97.64 \ -93.75}{ 0.00020 \ 93.75}[/tex]
ΔT = 2,075 10² C
ΔT = T₁-T₀ = 2,075 10²
T₁ = T₀ + 207.5
T₁ = 25+ 207.5
T₁ = 232.5 ºC
