When light encounters transparent materials, almost all of it passes directly through them. Glass, for example, is transparent to all visible light. ... Most of the light is either reflected by the object or absorbed and converted to thermal energy. Materials such as wood, stone, and metals are opaque to visible light.
Assume a device is designed to obtain a large potential difference by first charging a bank of capacitors connected in parallel and then activating a switch arrangement that in effect disconnects the capacitors from the charging source and from each other and reconnects them all in a series arrangement. The group of charged capacitors is then discharged in series. What is the maximum potential difference that can be obtained in this manner by using ten 500
Answer:
8 kV
Explanation:
Here is the complete question
Assume a device is designed to obtain a large potential difference by first charging a bank of capacitors connected in parallel and then activating a switch arrangement that in effect disconnects the capacitors from the charging source and from each other and reconnects them all in a series arrangement. The group of charged capacitors is then discharged in series. What is the maximum potential difference that can be obtained in this manner by using ten 500 μF capacitors and an 800−V charging source?
Solution
Since the capacitors are initially connected in parallel, the same voltage of 800 V is applied to each capacitor. The charge on each capacitor Q = CV where C = capacitance = 500 μF and V = voltage = 800 V
So, Q = CV
= 500 × 10⁻⁶ F × 800 V
= 400000 × 10⁻⁶ C
= 0.4 C
Now, when the capacitors are connected in series and the voltage disconnected, the voltage across is capacitor is gotten from Q = CV
V = Q/C
= 0.4 C/500 × 10⁻⁶ F
= 0.0008 × 10⁶ V
= 800 V
The total voltage obtained across the ten capacitors is thus V' = 10V (the voltages are summed up since the capacitors are in series)
= 10 × 800 V
= 8000 V
= 8 kV
Credit-Card Magnetic Strips Experiments carried out on the television show Mythbusters determined that a magnetic field of 1000 gauss is needed to corrupt the information on a credit card's magnetic strip. (They also busted the myth that a credit card can be demagnetized by an electric eel or an eelskin wallet.) Suppose a long, straight wire carries a current of 7.0A . How close can a credit card be held to this wire without damaging its magnetic strip?
Answer:
14 μm
Explanation:
The magnetic field due to a long straight wire is B = μ₀i/2πr where μ₀ = permeability of free space = 4π × 10⁻⁷ H/m, i = current = 7.0 A and r = distance of credit card from magnetic field.
So r = μ₀i/2πB since B = 1000 gauss = 1000 G × 1 T/10000 G = 0.1 T
r = 4π × 10⁻⁷ H/m × 7.0 A/(2π × 0.1 T)
r = 2 × 10⁻⁷ H/m × 7.0 A/0.1 T
r = 14 × 10⁻⁷ H/m × A/0.1 T
r = 140 × 10⁻⁷ m
r = 1.4 × 10⁻⁵ m
r = 14 × 10⁻⁶ m
r = 14 μm
Potential energy is best defined as which of the following?
A Mass energy
B Energy of Motion
C Stored Energy
D Energy of height
Answer: C. Stored energy
which particle have a mass of 1 u
Answer:
Explanation:
proton
Galvani wrongly believed that the frog’s leg twitched during his experiment due to _____.
Answer:
nerves
Explanation:
I think, I maybe wrong.
May you please help?
Choice-A is the main reason that people use the thing in the picture.
Which of the following could be an example of chemical weathering?
a. rocks tumbling against each other
b. water seeping into the ground, dissolving the limestone to form a cave
c. a waterfall boring out a whole in a rock under it
Answer: B
Explanation:
Answers A and C are examples of physical weathering while B is chemical weathering when water and lime mix it creates a reaction
Force of a Baseball Swing. A baseball has mass 0.153 kg . Part A If the velocity of a pitched ball has a magnitude of 44.5 m/s and the batted ball's velocity is 50.5 m/s in the opposite direction, find the magnitude of the change in momentum of the ball and of the impulse applied to it by the bat. Express your answer to three significant figures and include the appropriate units. P
Answer: 14.5 kg.m/s
Explanation:
Given
mass of baseball is [tex]m=0.153\ kg[/tex]
The initial speed of the ball is [tex]u=-44.5\ m/s[/tex]
the final speed of the ball is [tex]v=50.5\ m/s[/tex]
Impulse is given as a change in the momentum
[tex]\vec{J}=\Delta \vec{P}[/tex]
[tex]J=m(v-u)\\J=0.153(50.5-(44.5))\\J=0.153\times 95=14.535\ kg.m/s[/tex]
Change in momentum up to 3 significant figures is 14.5 kg.m/s
Impulse applied by a bat is also the same as the change in momentum
explain how renewable energy source help in the reducing the effects of global warming?
Answer:
Renewable energy minimizes carbon pollution and has a much lower impact on our environment. And it's having its moment in the sun. "Giving more New Yorkers access to renewable energy can allow them to reduce their own energy bills while reducing stress on the grid and demand for fossil fuel power.
What is an example of a combined approach in psychology?
Answer:
The third approach to cross-cultural studies of personality is the combined approach, which serves as a bridge between Western and indigenous psychology as a way of understanding both universal and cultural variations in personality
Explanation:
Answer:
The third approach to cross-cultural studies of personality is the combined approach, which serves as a bridge between Western and indigenous psychology as a way of understanding both universal and cultural variations in personality
What type of feeder is a snake? *
Answer:
slender-bodied non-stinging insect having iridescent wings that are outspread at rest; adults and nymphs feed on mosquitoes etc.
Explanation:
I hope this works. I have a snake and it helps to know this stuff
An electron is travelling in the positive x direction. A uniform electric field is in the negative y direction. If a uniform magnetic field with the appropriate magnitude and direction also exists in the region, the total force on the electron will be zero. The appropriate direction for the magnetic field is:Group of answer choicesthe negative y directioninto the pageout of the pagethe negative x directionthe positive y direction
Answer:
into the page
Explanation:
Since the uniform electric field is in the negative y direction so its is -E and the electron is travelling in the positive x direction, it experiences an electric force F = -e × -E = + eE, so the electric force is in the positive y direction. Now since the net force on the electron is zero in the region of the magnetic field, it follows that the direction of the magnetic force is opposite to that of the electric force. Since the electric force is in the positive y direction, the magnetic force is in the negative y direction.
By the right hand rule, since the magnetic force is in the negative y direction and the electron moves in the positive x direction, it follows that the magnetic field is in the positive z direction, into the page.
Easy physics question help.!!!
Answer: This is not easy lol
Explanation:
A copper plate is free to swing between the poles of a large electromagnet. When the field is turned up the plate Group of answer choices will swing faster. will not be affected at all. will brake and quickly come to rest. will swing with a larger amplitude, because it is pushed by the magnet. will become a permanent magnet.
Answer:
C: will brake and quickly come to rest.
Explanation:
Correct answer is option C because for the swinging motion of the copper plates between the magnetic field which is set up as a result of it being between the two magnetic poles, there will be a continuous change of magnetic field flux that will be linked with the swinging pendulum.
As a result of this continuous change of magnetic field flux, it makes eddy currents to be set up in the copper plate which according to the Lenz's laws of electromagnetic induction tries to oppose the motion of the swinging pendulum and finally will make it come to rest.
If each Coulomb of charge is given 20 Joules of energy, what is the voltage of the battery?
A. 20 V
B. 5 V
C. 10 V
D. Not enough info
Answer:
Explanation:
V = J/C
V = 20/1
= 20 v
Option A is the correct answer
An artificial satellite circling the Earth completes each orbit in 126 minutes. (a) Find the altitude of the satellite.
Answer:
Explanation:
Time period of rotation
T = 2πR/ V where R is radius of orbit and V is orbital velocity
Orbital velocity V = √ ( GM/R ) , m is mass of the earth .
T = 2πR √R / GM
T² = 4π²R³ / GM
Putting the values
( 126 x 60 )² = 4 x 3.14² x R³ / 6.67 x 10⁻¹¹ x 5.97 x 10²⁴
57.15 x 10⁶ = 39.44 x R³ / 39.82 x 10¹³
R³ = 577 X 10¹⁸
R = 8.325 x 10⁶ m
= 8325 km
Radius of earth = 6400 km
height of satellite = 8325- 6400 = 1925 km .
Mass is the amount of matter in an
object. Which statement is true?
A. A person's mass on the moon is less than it is on
Earth.
B. Whether on the Earth or the moon, a person's mass
is the same.
C. Gravity changes the amount of matter there is in an
object.
D. Mass is the same thing as weight.
If this is the stationary wall isn’t the ANSWER that there is no work being done? If not what is the correct answer and why? Help!!
Answer:
no work is done cause there is no movement of the wall
What fuel does a main-sequence star use for nuclear fusion?
oxygen (0)
petroleum
helium (He)
hydrogen (H)
Answer:
A main sequence star is powered by fusion of hydrogen into helium in its core
Explanation:
A car driver spends 3hrs driving at an average speed of 80km/hr, stops for 30 minutes to
have some rest, and then drives at an average speed of 90km/hr for 2 hours.
Calculate the average speed during the whole journey
Answer:
The average speed throughout the journey was 76.36 kilometers per hour.
Explanation:
Given that a car driver spends 3hrs driving at an average speed of 80km / hr, stops for 30 minutes to have some rest, and then drives at an average speed of 90km / hr for 2 hours, to determine the average speed during the whole journey the following calculation must be performed:
80 km / h x 3 = 240 km
90 km / h x 2 = 180 km
240 + 180 = 420 km
3 + 2 + 0.5 = 5.5 hours
420 / 5.5 = 76.36
Thus, the average speed throughout the journey was 76.36 kilometers per hour.
A solenoid of 2100 turns, area 10 cm2, and length 30 cm carries a current of 4.0 A. (a) Calculate the magnetic energy stored in the solenoid from 1/2 LI 2. J [2 points] 0 attempt(s) made (maximum allowed for credit
Answer:
E = 0.1472 J
Explanation:
Given that,
The number of turns in the solenoid, N = 2100
Area of the solenoid, A = 10 cm² = 0.001 m²
The length of the solenoid, l = 30 cm = 0.3 m
Current in the solenoid, I = 4 A
We need to find the magnetic energy stored in the solenoid. The expression for the stored energy is :
[tex]E=\dfrac{1}{2}LI^2[/tex]
Where
L is self inductance of the solenoid,
[tex]L=\dfrac{\mu_oN^2A}{l}\\\\L=\dfrac{4\pi \times 10^{-7}\times 2100^2\times 0.001}{0.3}\\\\L=0.0184\ H[/tex]
So,
[tex]E=\dfrac{1}{2}\times 0.0184\times 4^2\\\\E=0.1472\ J[/tex]
So, 0.1472 J of energy is stored in the solenoid.
A fox runs at a speed of 16 m/s and then stops to eat a rabbit. If this all took 120
seconds, what was his acceleration?
Answer:
a = 52s²
Explanation:
How to find acceleration
Acceleration (a) is the change in velocity (Δv) over the change in time (Δt), represented by the equation a = Δv/Δt. This allows you to measure how fast velocity changes in meters per second squared (m/s^2). Acceleration is also a vector quantity, so it includes both magnitude and direction.
Solve
We know initial velocity (u = 16), velocity (v = 120) and acceleration (a = ?)
We first need to solve the velocity equation for time (t):
v = u + at
v - u = at
(v - u)/a = t
Plugging in the known values we get,
t = (v - u)/a
t = (16 m/s - 120 m/s) -2/s2
t = -104 m/s / -2 m/s2
t = 52 s
2. A kayaker is paddling south at 2.50 m/s, and encounters a weird current moving 1.15 m/s west.
What is the resultant velocity?
Answer:
v = 2.91 m/s
Explanation:
Given that,
A kayaker is paddling south at 2.50 m/s, and encounters a weird current moving 1.15 m/s west.
We need to find the resultant velocity. Both velocities are perpendicular to each other. So,
[tex]v=\sqrt{v_1^2+v_2^2} \\\\=\sqrt{2.5^2+1.5^2} \\\\=2.91\ m/s[/tex]
So, the magnitude of the resultant velocity is equal to 2.91 m/s.
Although planets orbit the Sun in ellipses, all the planetary orbits are fairly close to circular and not very eccentric.
True
False
Answer:
False
Explanation:
The Sun rotates in this same, right-hand-rule direction. All planetary orbits lie in nearly the same plane. All planetary orbits are nearly circular (eccentricity near zero).
Rate as Brainliest please
A car weighing 1,500kg possesses 20 000 units of momentum. What would be the car's new momentum if it's velocity was tripled
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Explanation:
Establishing a potential difference The deflection plates in an oscilloscope are 10 cm by 2 cm with a gap distance of 1 mm. A 100 volt potential difference is suddenly applied to the initially uncharged plates through a 1000 ohm resistor in series with the deflection plates. How long does it take for the potential difference between the deflection plates to reach 60 volts
Answer:
[tex]1.62\times 10^{-8}\ \text{s}[/tex]
Explanation:
[tex]\epsilon_0[/tex] = Vacuum permittivity = [tex]8.854\times 10^{-12}\ \text{F/m}[/tex]
[tex]A[/tex] = Area = [tex]10\times 2\times 10^{-4}\ \text{m}^2[/tex]
[tex]d[/tex] = Distance between plates = 1 mm
[tex]V_c[/tex] = Changed voltage = 60 V
[tex]V[/tex] = Initial voltage = 100 V
[tex]R[/tex] = Resistance = [tex]1000\ \Omega[/tex]
Capacitance is given by
[tex]C=\dfrac{\epsilon_0A}{d}\\\Rightarrow C=\dfrac{8.854\times 10^{-12}\times 10\times 2\times 10^{-4}}{1\times 10^{-3}}\\\Rightarrow C=1.7708\times 10^{-11}\ \text{F}[/tex]
We have the relation
[tex]V_c=V(1-e^{-\dfrac{t}{CR}})\\\Rightarrow e^{-\dfrac{t}{CR}}=1-\dfrac{V_c}{V}\\\Rightarrow -\dfrac{t}{CR}=\ln (1-\dfrac{V_c}{V})\\\Rightarrow t=-CR\ln (1-\dfrac{V_c}{V})\\\Rightarrow t=-1.7708\times 10^{-11}\times 1000\ln(1-\dfrac{60}{100})\\\Rightarrow t=1.62\times 10^{-8}\ \text{s}[/tex]
The time taken for the potential difference to reach the required level is [tex]1.62\times 10^{-8}\ \text{s}[/tex].
Each of the two grinding wheels has a diameter of 6 in., a thickness of 3/4 in., and a specific weight of 425 lb/ft3. When switched on, the machine accelerates from rest to its operating speed of 3450 rev/min in 5 sec. When switched off, it comes to rest in 35 sec. Determine the motor torque and frictional moment, assuming that each is constant. Neglect the effects of the inertia of the rotating motor armature.
Answer:
[tex]0.842\ \text{lb ft}[/tex]
[tex]0.1052\ \text{lb ft}[/tex]
Explanation:
d = Diameter of wheel = 6 in
r = Radius = 3 in = [tex]\dfrac{3}{12}=0.25\ \text{ft}[/tex]
t = Thickness = [tex]\dfrac{3}{4}=0.75\ \text{in}=\dfrac{0.75}{12}\ \text{ft}[/tex]
w = Specific weight = [tex]425\ \text{lb/ft}^3[/tex]
[tex]t_2[/tex] = Time taken to slow down = 35 s
[tex]t_1[/tex] = Time taken to reach operating speed = 5 s
[tex]\omega[/tex] = Angular velocity = [tex]3450\times \dfrac{2\pi}{60}\ \text{rad/s}[/tex]
Weight is given by
[tex]W=2\pi r^2tw\\\Rightarrow W=2\pi\times 0.25^2\times \dfrac{0.75}{12}\times 425\\\Rightarrow W=10.43\ \text{lbs}[/tex]
Mass is given by
[tex]m=\dfrac{W}{g}\\\Rightarrow m=\dfrac{10.43}{32}\\\Rightarrow m=0.326\ \text{lb}[/tex]
Moment of inertia is given by
[tex]I=\dfrac{mr^2}{2}\\\Rightarrow I=\dfrac{0.326\times 0.25^2}{2}\\\Rightarrow I=0.01019\ \text{lb ft}^2[/tex]
Angular acceleration while slowing down is given by
[tex]\alpha_f=\dfrac{\omega}{t_2}\\\Rightarrow \alpha_f=\dfrac{3450\times \dfrac{2\pi}{60}}{35}\\\Rightarrow \alpha_f=10.32\ \text{rad/s}^2[/tex]
Frictional moment is given
[tex]\tau_f=I\alpha_f\\\Rightarrow \tau_f=0.01019\times 10.32\\\Rightarrow \tau_f=0.1052\ \text{lb ft}[/tex]
Frictional moment is [tex]0.1052\ \text{lb ft}[/tex]
Angular acceleration while speeding up is given by
[tex]\alpha=\dfrac{\omega}{t_1}\\\Rightarrow \alpha=\dfrac{3450\times \dfrac{2\pi}{60}}{5}\\\Rightarrow \alpha=72.26\ \text{rad/s}^2[/tex]
Motor torque is given by
[tex]\tau_m=\tau_f+I\alpha\\\Rightarrow \tau_m=0.1052+0.01019\times 72.26\\\Rightarrow \tau_m=0.842\ \text{lb ft}[/tex]
Motor torque is [tex]0.842\ \text{lb ft}[/tex].
A +3.4 x 10-6 C test charge experiences forces from two other nearby charges: a 3 N force due east and a 15 N force due west. What are the magnitude and direction of the electric field st the location of the test charge?
Answer:
3.53×10⁶ N/c due west
Explanation:
From the question
E = F'/q........................ Equation 1
Where E = Electric Field, F = Net Force, q = Charge.
But,
F' = F₂-F₁...................... Equation 2
Substitute equation 2 into equation 1
E = (F₂-F₁)/q................ Equation 3
Given: F₁ = 3 N due east, F₂ = 15 N due west, q = 3.4×10⁻⁶ C
Substitute these values into equation 1
E = (15-3)/(3.4×10⁻⁶)
E = 12/(3.4×10⁻⁶)
E = 3.53×10⁶ N/c due west
A van has a weight of 4000 lb and center of gravity at Gv. It carries a fixed 900 lb load which has a center of gravity at Gl. If the van is traveling at 40 ft/s, determine the distance it skids before stopping. The brakes cause all the wheels to lock or skid. The coefficient of kinetic friction between the wheels and the pavement is . Assume that the two rear wheels are one normal, NB, and the two front wheels are one normal, NA.
Answer:
x = 25 / μ [ ft]
Explanation:
To solve this exercise we can use Newton's second law.
Let's set a reference system where the x axis is parallel to the road
Y axis
N_B + N_A - W_van - W_load = 0
N_B + N_A = W_van + W_load
X axis
fr = ma
a = fr / m
the total mass is
m = (W_van + W_load) / g
the friction force has the expression
fr = μ N_{total}
fr = μy (W_van + W_load)
we substitute
a = μ (W_van + W_load) [tex]\frac{g}{W_van + W_load}[/tex]
a = μ g
taking the acceleration let's use the kinematic relations where the final velocity is zero
v² = v₀² - 2 a x
0 = v₀² -2a x
x = [tex]\frac{v_o^2}{2a}[/tex]
x = [tex]\frac{v_o^2}{2 \mu g}[/tex]
x = [tex]\frac{40^2}{2 \ 32 \ \mu}[/tex]
x = 25 / μ [ ft]
A mass weighing 24 pounds, attached to the end of a spring, stretches it 4 inches. Initially, the mass is released from rest from a point 4 inches above the equilibrium position. Find the equation of motion. (Use g
Answer:
The equation of motion is [tex]x(t)=-[/tex][tex]\frac{1}{3} cos4\sqrt{6t}[/tex]
Explanation:
Lets calculate
The weight attached to the spring is 24 pounds
Acceleration due to gravity is [tex]32ft/s^2[/tex]
Assume x , is spring stretched length is ,4 inches
Converting the length inches into feet [tex]x=\frac{4}{12} =\frac{1}{3}feet[/tex]
The weight (W=mg) is balanced by restoring force ks at equilibrium position
mg=kx
[tex]W=kx[/tex] ⇒ [tex]k=\frac{W}{x}[/tex]
The spring constant , [tex]k=\frac{24}{1/3}[/tex]
= 72
If the mass is displaced from its equilibrium position by an amount x, then the differential equation is
[tex]m\frac{d^2x}{dt} +kx=0[/tex]
[tex]\frac{3}{4} \frac{d^2x}{dt} +72x=0[/tex]
[tex]\frac{d^2x}{dt} +96x=0[/tex]
Auxiliary equation is, [tex]m^2+96=0[/tex]
[tex]m=\sqrt{-96}[/tex]
=[tex]\frac{+}{} i4\sqrt{6}[/tex]
Thus , the solution is [tex]x(t)=c_1cos4\sqrt{6t}+c_2sin4\sqrt{6t}[/tex]
[tex]x'(t)=-4\sqrt{6c_1} sin4\sqrt{6t}+c_2[/tex] [tex]4\sqrt{6}[/tex] [tex]cos4\sqrt{6t}[/tex]
The mass is released from the rest x'(0) = 0
[tex]=-4\sqrt{6c_1} sin4\sqrt{6(0)}+c_2[/tex] [tex]4\sqrt{6}[/tex] [tex]cos4\sqrt{6(0)}[/tex] =0
[tex]c_2[/tex] [tex]4\sqrt{6} =0[/tex]
[tex]c_2=0[/tex]
Therefore , [tex]x(t)=c_1[/tex] [tex]cos 4\sqrt{6t}[/tex]
Since , the mass is released from the rest from 4 inches
[tex]x(0)= -4[/tex] inches
[tex]c_1 cos 4\sqrt{6(0)} =-\frac{4}{12}[/tex] feet
[tex]c_1=-\frac{1}{3}[/tex] feet
Therefore , the equation of motion is [tex]-\frac{1}{3} cos4\sqrt{6t}[/tex]