Answer:
Jesseca wanted to create a material that reflected most of the light that fell on it.
Explanation: The Graphite was the material in the passage that had reflected most of the light.
A resistor and an inductor are connected in series to a battery. The time constant for the circuit represents the time required for the current to reach:_______.
A.100% of the maximum current.
B. 75% of the maximum current.
C. 37% of the maximum current.
D. 25% of the maximum current.
E. 63% of the maximum current.
an astronaut is said to be weightless when he/she travells in a satellite . does it mean that the earthdoes not attract him/her ?
Answer:
It does attract
Explanation:
But due to the lack of gravitational pull of the earth he/she feels weightless I hope this helps you
When a cube is inscribed in a sphere of radius r, the length Lof a side of the cube is . If a positive point charge Qis placed at the center of the spherical surface, the ratio of the electric flux sphereat the spherical surface to the flux cubeat the surface of the cube is(sphere / cube)
Answer:
Ф_cube /Ф_sphere = 3 /π
Explanation:
The electrical flow is
Ф = E A
where E is the electric field and A is the surface area
Let's shut down the electric field with Gauss's law
Фi = ∫ E .dA = [tex]q_{int}[/tex] / ε₀
the Gaussian surface is a sphere so its area is
A = 4 π r²
the charge inside is
q_{int} = Q
we substitute
E 4π r² = Q /ε₀
E = 1 / 4πε₀ Q / r²
To calculate the flow on the two surfaces
* Sphere
Ф = E A
Ф = 1 / 4πε₀ Q / r² (4π r²)
Ф_sphere = Q /ε₀
* Cube
Let's find the side value of the cube inscribed inside the sphere.
In this case the radius of the sphere is half the diagonal of the cube
r = d / 2
We look for the diagonal with the Pythagorean theorem
d² = L² + L² = 2 L²
d = √2 L
we substitute
r = √2 / 2 L
r = L / √2
L = √2 r
now we can calculate the area of the cube that has 6 faces
A = 6 L²
A = 6 (√2 r)²
A = 12 r²
the flow is
Ф = E A
Ф = 1 / 4πε₀ Q/r² (12r²)
Ф_cubo = 3 /πε₀ Q
the relationship of these two flows is
Ф_cube /Ф_sphere = 3 /π
To initiate a nuclear reaction, an experimental nuclear physicist wants to shoot a proton into a 5.50-fm-diameter 12C nucleus. The proton must impact the nucleus with a kinetic energy of 1.80 MeV. Assume the nucleus remains at rest.
Required:
a. With what speed must the proton be fired toward the target?
b. Through what potential difference must the proton be accelerated from rest to acquire this speed?
Answer:
Explanation:
kinetic energy required = 1.80 MeV
= 1.8 x 10⁶ x 1.6 x 10⁻¹⁹ J
= 2.88 x 10⁻¹³ J
If v be the velocity of proton
1/2 x mass of proton x v² = 2.88 x 10⁻¹³
= .5 x 1.67 x 10⁻²⁷ x v² = 2.88 x 10⁻¹³
v² = 3.45 x 10¹⁴
v = 1.86 x 10⁷ m /s
If V be the potential difference required
V x e = kinetic energy . where e is charge on proton .
V x 1.6 x 10⁻¹⁹ = 2.88 x 10⁻¹³
V = 1.8 x 10⁶ volt .
At what frequency should a 200-turn, flat coil of cross sectional area of 300 cm2 be rotated in a uniform 30-mT magnetic field to have a maximum value of the induced emf equal to 8.0 V
Answer:
The frequency of the coil is 7.07 Hz
Explanation:
Given;
number of turn of the coil, N = 200 turn
area of the coil, A = 300 cm² = 0.03 m²
magnitude of magnetic field, B = 30 mT = 0.03 T
maximum value of induced emf, E = 8 V
The maximum induced emf in the coil is given by;
E = NBAω
E = NBA(2πf)
[tex]f = \frac{E_{max}}{2\pi*NBA}[/tex]
where;
f is the frequency of the coil
[tex]f = \frac{E_{max}}{2\pi*NBA}\\\\f = \frac{8}{2\pi(200)(0.03)(0.03)} \\\\f = 7.07 \ Hz[/tex]
Therefore, the frequency of the coil is 7.07 Hz
in a 200 m swimming competition,a swimmer took 12.3s to complete the first lap,12.5 for the second lap,12.7 for the third lap and 12.6 for the fourth lap.Each lap is 50 m long.Find the average speed and average velocity of the swimmer
Explanation:
Distance is the length of the path. Displacement is the difference between the final position and the initial position.
Speed = distance / time
= (50 m + 50 m + 50 m + 50 m) / (12.3 s + 12.5 s + 12.7 s + 12.6 s)
= (200 m) / (50.1 s)
= 3.99 m/s
Velocity = displacement / time
= (50 m − 50 m + 50 m − 50 m) / (12.3 s + 12.5 s + 12.7 s + 12.6 s)
= (0 m) / (50.1 s)
= 0 m/s
When a p-n-p transistor is operated in saturation region, then its ___________
Answer:
Base-emitter and Base-collector junctions are forward biased
A sailboat moves north for a distance of 10.00 km when blown by a wind from the exact south with a force of 5.00 x 10^4 N.
How much work was done by the wind?
Answer:
5*10^8Nm
Explanation:
work done= displacement* force
Since the wind blows in the direction that the boats want to travel, all values would be positive.
10*10^3*(5*10^4)=5.00*10^8Nm
Answer:
5 x 10⁸ J
Explanation:
Recall that
Work Done = Force x Distance Traveled in the direction of the force
We are given :
Force = 5.00 x 10⁴ = 50,000 N
Distance Travelled in the direction of the force = 10.00 km = 10,000 m
Hence,
Work Done = 50,000 N x 10,000 m
= 500,000,000 J
= 5 x 10⁸ J
Your bedroom has a rectangular shape and you want to measure its size. You use a tape that is precise to 0.001 m and find that the shortest wall in the room is 3.547 m long. The tape, however, is too short to measure the length of the second wall, so you use a second tape, which is longer but only precise to 0.01 m. You measure the second wall to be 4.79 m long. Which of the following numbers is the most precise estimate that you can obtain from your measurements for the area of your bedroom?
a) 30 m^2.
b) 31.4 m^2.
c) 31.37 m^2.
d) 31.371 m^2.
Your bedroom has a rectangular shape, and you want to measure its area. You use a tape that is precise to 0.001 and find that the shortest wall in the room is 3.547 long. The tape, however, is too short to measure the length of the second wall, so you use a second tape, which is longer but only precise to 0.01 . You measure the second wall to be 4.79 long. Which of the following numbers is the most precise estimate that you can obtain from your measurements for the area of your bedroom?
b)If your bedroom has a circular shape, and its diameter measured 6.32 , which of the following numbers would be the most precise value for its area?
a)30 m^2
b) 31.4 m^2
c)31.37 m^2
d)31.371 m^2
Answer:
Part A
[tex]A = 16.99 \ m^2[/tex]
Part B
[tex]A_r =31.37 \ m^2[/tex]
Explanation:
From the question we are told that
The shortest wall is [tex]x = 3.547 \ m[/tex]
The length of the second wall is [tex]y = 4.79 \ m[/tex]
Generally the area is mathematically evaluated as
[tex]A = x * y[/tex]
=> [tex]A = 3.547 * 4.79[/tex]
=> [tex]A = 16.99 \ m^2[/tex]
Given that the diameter is d = 6.32
Then the area is
[tex]A_r = \pi \frac{d^2}{4}[/tex]
[tex]A_r =3.142 * \frac{6.32^2}{4}[/tex]
[tex]A_r =31.37 \ m^2[/tex]
With what minimum speed must you toss a 130 g ball straight up to just touch the 14-m-high roof of the gymnasium if you release the ball 1.1 m above the ground
THIS IS THE COMPLETE QUESTION BELOW
With what minimum speed must you toss a 130 g ball straight up to just touch the 14-m-high roof of the gymnasium if you release the ball 1.1 m above the ground
And what speed does the ball hit the ground? Solve this problem using energy.
Answer
a)minimum speed must you toss a 130 g is 15.9090m/s
b)speed the ball hit the ground is 16.57m/s
Explanation:
a)We know that For any closed/isolated system, the total energy is CONSERVED.
K.E. lost by the ball=The change in P.E of the ball at 1.1m above the ground as well as the P.E. of the ball at 14 m-high roof
This statement can be expressed as the expression below from K.E and P.E energy formula
P.E. = mgh
K.E. = (1/2)mv^2
Therefore,
(mgh1 - mgh2)=(1/2)mv^2
Where h2=the ball height above the ground=1.1m
h1=ball height at roof of the gymnasium= 14m
Then if we substitute we have
[(10) x (0.14) x (9.81)] - [(1.1) x (0.14) x (9.81)] = (1/2)(0.14)(v^2)
16.45137=0.065V^2
V=15.9090m/s
minimum speed must you toss a 130 g is 15.9090m/s
b)To calculate the speed the ball hit the ground?
This is the highest point (14m-high roof),and the type of the energy the ball possesses is Po.tential energy only.
At the lowest point (ground), the energy the ball possesses is K.E. only.
P.E at 10m-high roof = K.E. at ground.
(14) x (0.13) x (9.81) = (1/2) x (0.13) x v^2
17.8542= 0.065V^2
V= 16.57
Therefore,And speed the ball hit the ground is 16.57m/s
A person speed walking down a street covers 20m in 5s. What is the
speed of the individual? *
Answer:
4 m/s.
Explanation:
The following data were obtained from the question:
Distance travalled (d) = 20 m
Time (t) = 5 secs
Speed (S) =?
Speed is defined as the rate of change of distance moved with time. Mathematically, it is expressed as:
Speed (S) = Distance (d) /time (t)
S = d/t
With the above formula, we can easily calculate the speed of the individual as follow:
Distance travalled (d) = 20 m
Time (t) = 5 secs
Speed (S) =?
S = d/t
S = 20/5
S = 4 m/s
Therefore, the speed of the individual is 4 m/s
You slide a coin across the floor, and observe that it slows down and eventually stops. A sensitive thermometer shows that its temperature increased. What can we conclude
Answer:
The mechanical energy of the coin has been used up in doing work against friction.
Explanation:
When two bodies in contact move against one another, friction comes to play. Friction converts energy in such a system to heat which raises the temperature of the body, with most lost to the ambient environment. Sliding the coins on the floor transfers energy from your hand into the mechanical energy of the coin as it moves across the floor. Fiction between the coin and the surface of the floor gradually slows the coin down by converting its energy to heat (which raises the temperature of the coin as detected by the thermometer) until the coin comes to a halt.
A ruby laser delivers a 16.0-ns pulse of 4.20-MW average power. If the photons have a wavelength of 694.3 nm, how many are contained in the pulse
Answer:
The value is [tex]n = 2.347 *10^{17} \ photons[/tex]
Explanation:
From the question we are told that
The amount of power delivered is [tex]P = 4.20 \ M W = 4.20 *10^{6} \ W[/tex]
The time taken is [tex]t = 16.0ns = 16.0 *10^{-9} \ s[/tex]
The wavelength is [tex]\lambda = 694.3 \ nm = 694.3 *10^{-9} \ m[/tex]
Generally the energy delivered is mathematically represented as
[tex]E = P * t = \frac{n * h * c }{\lambda }[/tex]
Where [tex]h[/tex] is the Planck's constant with value [tex]h = 6.262 *10^{-34} \ J \cdot s[/tex]
c is the speed of light with value [tex]c = 3.0*10^{8} \ m/s[/tex]
So
[tex]4.20 *10^{6} * 16*10^{-9}= \frac{n * 6.626 *10^{-34} * 3.0*10^{8} }{694.3 *10^{-9}}[/tex]
=> [tex]n = 2.347 *10^{17} \ photons[/tex]
An 8-hour exposure to a sound intensity level of 90.0 dB may cause hearing damage. What energy in joules falls on a 0.800-cm-diameter eardrum so exposed?
Answer:
1.4E-3J
Explanation:
Given that
Time = 8hrs = 28.8E3 seconds
Intensity= 90dB
D= 0.008m
Radius= 0.004m
So intensity is sound level Bis
10dBlog(I/Io)
I= 10 (B/10dB)Io
= 10( 90/10) x 10^-12
=0.001W/m²
But we know that
I = P/A
P= I πr²
= 5.02 x10^-8W
But energy is power x time
So E= 5.02E-8 x 28.8E3
= 1.4E-3J
Answer:
1.44x10⁻³J
Explanation:
Given :
Time = 8hrs *(3600secs/1hr)= 28.8*10³seconds
Intensity= 90dB
D= 0.008m
Radius=0.008m/2
=0.004m
the sound level in decibel can be expressed below as
I=10dBlog[I/I₀]
where I₀=10⁻¹²/m² which is the refrence intensity
90=10log[I/10⁻¹²]
I=0.001W/m²
we know that intensity of the wave which id the average rate per unit area which energy is transfered can be calculated using below formular
I = P/A
where P= powerr which is renergy transfer at a time
A= area= πr²
making P subject of formular we have
P= I πr²
= 5.02 x10⁻⁸W
Energy =power x time
E=28800*5*10⁻⁸
=0.001443J
therefore,the energy in joules is 1.44x10⁻³J
Please help!
Much appreciated!
Answer:
Ts = 3.0×10¯² sec
Explanation:
From the question given:
Ts = 2π √(4.5×10¯² Kg / 2.0×10³ Kg/s²)
The above expression can be evaluated as follow:
Pi (π) = 3.14
Ts = 2π √(4.5×10¯² / 2.0×10³)
Ts = 2 × 3.14 √(4.5×10¯² / 2.0×10³)
Ts = 6.28 × √(2.25×10¯⁵)
Ts = 6.28 × 4.74×10¯³
Ts = 3.0×10¯² sec
The downward pull on an object due to gravity is the object’s ______. A. volume B. mass C. weight D. matter
Answer:
C. Weight
Explanation:
A push or pull is a force. The force caused by gravity is called weight.
Answer:
C: Weight
Explanation:
What happens when two waves meet while they travel through the same medium
Wave Interference or Interference of wave
What should a model of the rock cycle show as the process that changes metamorphic rock to igneous rock?
Answer:
Rock cycle describes the concept in geology that shows the changes in the rock type in the geologic time.
Many processes undergoes in the rock cycle that leads to transition of rocks, the process that changes metamorphic rock to igneous rock is melting and crystallization. The metamorphic rock melts under high pressure and temperature and which crystallizes into a completely different kind of rock, called igneous rock.
Answer:
Melting followed by cooling
Can someone solve the blank questions? I am really having trouble solving them. Thank you!
Answer:
<In the attachment>
Explanation:
There's not really much for me to say here I feel. On 7)b) you appear to let y=0 for some reason, so I redid that one without doing that just in case. Just look at what I did and take notes for the future.
An air-filled capacitor consists of two parallel plates, each with an area of 8 cm^2 , separated by a distance 2.9 mm. A 22 V potential difference is applied to these plates.
What is the magnitude of the surface charge density on each plate?
Answer:
The magnitude of the surface charge density on each plate is 6.714 x 10⁻⁸ C/m²
Explanation:
Given;
area of the parallel plates, A = 8 cm² = 8 x 10⁻⁴ m²
distance between the plates, d = 2.9 mm = 0.0029 m
potential difference applied to the plates, V = 22 V
The electric field between the plates is given by;
[tex]E = \frac{V}{d} \\\\E = \frac{22}{2.9*10^{-3}}\\\\E = 7586.207 \ V/m[/tex]
The surface charge density is given by;
σ = ε₀E
σ = (8.85 x 10⁻¹²)(7586.207)
σ = 6.714 x 10⁻⁸ C/m²
Therefore, the magnitude of the surface charge density on each plate is 6.714 x 10⁻⁸ C/m²
An inductor has inductance of 0.260 H and carries a current that is decreasing at a uniform rate of 18.0 mA/s.
Required:
Find the self-induced emf in this inductor.
Answer:
The self-induced emf in this inductor is 4.68 mV.
Explanation:
The emf in the inductor is given by:
[tex] \epsilon = -L\frac{dI}{dt} [/tex]
Where:
dI/dt: is the decreasing current's rate change = -18.0 mA/s (the minus sign is because the current is decreasing)
L: is the inductance = 0.260 H
So, the emf is:
[tex] \epsilon = -L\frac{dI}{dt} = -0.260 H*(-18.0 \cdot 10^{-3} A/s) = 4.68 \cdot 10^{-3} V [/tex]
Therefore, the self-induced emf in this inductor is 4.68 mV.
I hope it helps you!
The self-induced emf in this inductor is 4.68 mv.
Calculation of the emf in the inductor:Here
E = -LdI/dt
here
dI/dt represents the the decreasing current's rate change = -18.0 mA/s
the minus sign is due to the current is decreasing
L represents the inductance = 0.260 H
Now the emf should be
= -0260H * (-18.0.10^-3)
= 4.68 mv
hence, The self-induced emf in this inductor is 4.68 mv.
Learn more about current here: https://brainly.com/question/17080022
What Is experimental
design?
Jane is sliding down a slide. What kind of motion is she demonstrating? A. translational motion B. rotational motion C. vibrational motion D. transverse motion
Answer:
Transational Motion
Explanation:
What magnetic field strength will allow the electrons to pass through without being deflected?
Answer:
Explanation:
If magnetic field exists parallel to the direction of motion of electron , no force will act on the electrons and hence there will be no deflection in them .
In such cases , the magnitude of magnetic field is immaterial . No matter how high or low magnitude of magnetic field be , if it is parallel to the velocity of electron , it will not be deflected as the force created on them will be zero.
Only in case magnetic field makes some angle with the direction of velocity , force will be created and electron will be deflected .
What is solar physics?
what is the percent uncertainty in the volume of a spherical beach ball whose radius is r = .84 plus or minus .04 m?
Answer:
The percent uncertainty in the volume [tex]\frac{\delta V}{V} * 100 = 14.286\%[/tex]
Explanation:
From the question we are told that
The radius is [tex]r = 0.84 \pm 0.04 \ m[/tex]
From the given value
The uncertainty of radius is [tex]\delta r = 0.04[/tex]
Generally the volume of a spherical beach ball is mathematically represented as
[tex]V = \frac{4\pi }{3}* r^3[/tex]
Now taking the log of both sides
[tex]log V = log [\frac{4\pi}{3} ] * r^3[/tex]
=> [tex]log V = log [\frac{4\pi}{3} ] + log( r^3)[/tex]
=> [tex]log V = log [\frac{4\pi}{3} ] + 3log( r)[/tex]
Differentiating both sides
[tex]\frac{1}{V} \delta V = 0 + 3 [\frac{1}{r} ] \ \delta r[/tex]
Now converting them to percentage by multiplying by 100
[tex]\frac{\delta V}{V} * 100 = [\frac{ 3 \delta r }{r} ] \ * 100[/tex]
=> [tex]\frac{\delta V}{V} * 100 = [\frac{ 3 * 0.04 }{ 0.84} ] \ * 100[/tex]
=> [tex]\frac{\delta V}{V} * 100 = 14.286\%[/tex]
Three identical very dense masses of 3500 kg each are placed on the x axis. One mass is at x1 = -100 cm , one is at the origin, and one is at x2 = 320 cm . Part A What is the magnitude of the net gravitational force Fgrav on the mass at the origin due to the other two masses? Take the gravitational constant to be G = 6.67×10−11 N⋅m2/kg2 . Express your answer in newtons to three significant figures. Part B What is the direction of the net gravitational force on the mass at the origin due to the other two masses? +x direction or -x direction.
Answer:
A) 7.37 x 10^-4 N
B) The resultant force will be towards the -x axis
Explanation:
The three masses have mass = 3500 kg
For the force of attraction between the mass at the origin and the mass -100 cm away:
distance r = 100 cm = 1 m
gravitational constant G= 6.67×10^−11 N⋅m^2/kg^2
Gravitational force of attraction [tex]F_{g}[/tex] = [tex]\frac{Gm^{2} }{r^{2} }[/tex]
where G is the gravitational constant
m is the mass of each of the masses
r is the distance apart = 1 m
substituting, we have
[tex]F_{g}[/tex] = [tex]\frac{6.67*10^{-11}*3500^{2} }{1^{2} }[/tex] = 8.17 x 10^-4 N
For the force of attraction between the mass at the origin and the mass 320 cm away
distance r = 320 cm = 3.2 m
[tex]F_{g}[/tex] = [tex]\frac{Gm^{2} }{r^{2} }[/tex]
substituting, we have
[tex]F_{g}[/tex] = [tex]\frac{6.67*10^{-11}*3500^{2} }{3.2^{2} }[/tex] = 7.98 x 10^-5 N
Resultant force = (8.17 x 10^-4 N) - (7.98 x 10^-5 N) = 7.37 x 10^-4 N
B) The resultant force will be towards the -x axis
A cruise started its trip 8:00. Its average speed was 100 km/h.
When it travelled 2/5 of its journey by 12:00, the boat changed
its speed. If the boat was required to arrive at the destination at
17:00, what average speed must the boat travel at for the
remaining journey?
Answer:
120 k/m
Explanation:
Answer: 120
Explanation:
A woman rides a carnival Ferris wheel at radius 16 m, completing 4.5 turns about its horizontal axis every minute. What are (a) the period of the motion, and the magnitude of her centripetal acceleration at (b) the highest point and (c) the lowest point
Answer:
a)13.33s
b)at highest point, the centripetal acceleration has its direction at downward path towards the center of the circular path, and the radius vector has its direction upward. Then acceleration=3.555m/s^2
c)c)at lowest point the centripetal acceleration has its direction upward towards the center of the circular path, and the radius vector has its direction downward Then acceleration=3.555m/s^2
Explanation
a)number of turns= 4.5
radius= 16m
We know that the period is the time taken by the wheel to complete one turn which can be calculated using below expresion
T= t/n
Where T= period of motion
t= Time taken by the wheel to finish n turns where our n= 4.5
T= (1×60)/4.5= 13.33s
Hence the period is 13.33s
Then the speed of the woman v= 2πr/T
v= (2×π×16)/13.33
v=7.5417m/s
b)at highest point, the centripetal acceleration has its direction at downward path towards the center of the circular path, and the radius vector has its direction upward.
a= v^2/r
Where r= radius
v= speed of the woman= 7.5417m/s
a=(7.5417m/s)^2/16
a=3.555m/s^2
The centripetal acceleration and radius vector are in opposite direction
c)at lowest point the centripetal acceleration has its direction upward towards the center of the circular path, and the radius vector has its direction downward
The magnitude of the acceleration is calculated below
a= v^2/r
Where r= radius
v= speed of the woman= 7.5417m/s
a=(7.5417m/s)^2/16
a=3.555m/s^2
Joe rides south on his bicycle in a straight line for 16 min with an average speed of 11.6 km/h , how far has he ridden? Answer in units of km.
Explanation:
Distance = speed × time
d = (11.6 km/h) (16 min × 1 hr / 60 min)
d = 3.09 km
Answer: distance = 3.09 km
Explanation: Distance = speed × time
distance = (11.6 km/h) (16 min × 1 hr / 60 min)
distance = 3.09 km
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