Suppose we measure the energy stored in some inductor to be E when there is a current I running through it. If I double the current in the inductor, the new total energy will become _____.
a. 8E
b. 2E
c. E
d. E/4
e. E/2
f. 4E
Answer:
If I double the current in the inductor, the new total energy will become 4E (option f).
Explanation:
The coil or inductor is a passive component made of an insulated wire that stores energy in the form of a magnetic field due to its form of coiled turns of wire, through a phenomenon called self-induction. In other words, inductors store energy in the form of a magnetic field. The energy stored in the space where there is a magnetic field in the inductor is:
[tex]E=\frac{1}{2} *L*I^{2}[/tex]
where E is Energy [J], L is Inductance [H] and I is Current [A].
If you double the current in the inductor, then the new value of the current is I'= 2*I. So replacing the new total energy is:
[tex]E'=\frac{1}{2} *L*I'^{2}=\frac{1}{2} *L*(2*I)^{2}=\frac{1}{2} *L*4*I^{2}=4*\frac{1}{2} *L*I^{2}[/tex]
Then:
[tex]E'=4*E[/tex]
If I double the current in the inductor, the new total energy will become 4E (option f).
A diver makes 0.50 revolutions on the way from a 9.6-m-high platform to the water. Assuming zero initial vertical velocity, find the diver's average angular velocity during a dive.
Answer:
ω = 0.36 rev/s = 2.24 rad/s
Explanation:
First, we will find the time taken by the diver to reach the water. For this we use 2nd equation of motion:
h = Vi t + (1/2)gt²
where,
h = height = 9.6 m
Vi = initial vertical velocity = 0 m/s
t = time taken = ?
g = 9.8 m/s²
Therefore,
9.6 m = (0 m/s)(t) + (1/2)(9.8 m/s²)t²
t = √1.95 s²
t = 1.4 s
Now, the average angular speed of diver will be:
ω = No. of Revolutions/t
ω = 0.5 rev/1.4 s
ω = 0.36 rev/s = 2.24 rad/s
The tension in a string from which a 7 kg
object is suspended in an elevator is equal to
74 N.
A) What is magnitude of the acceleration a of
the elevator? The acceleration of gravity is
9.8 m/s^2. Answer in units of m/s^2
B) What is its direction?
Answer:
0.77 m/s^2
Explanation:
Notice that the weight of the 7 kg mass is calculated via:
weight = m * g = 7 * 9.8 N = 68.6 N
Since the tension in the string is larger (74 N), then the elevator is moving upward and the net force on the object is equal to:
74 N - 68.6 N = 5.4 N
Which tells us that the acceleration of the object is:
F = m * a
5.4 N = 7 kg * a
a = 5.4 /7 m/s^2
a = 0.77 m/s^2
and this must be the same as the acceleration of the elevator since object and elevator are moving together.
[K1 A2 T1 C1] A golfer strikes a golf ball on level ground.
The ball leaves the ground with an initial velocity of 42 m/s [32o
above horizontal].
a. Draw a vector diagram to describe the situation of the of golf
ball with initial velocity.
b. Find the range (horizontal distance) of the golf ball travelled.
c. Find the maximum height (vertical distance) the golf ball
reached.
Answer:
Explanation:
See the file attached .
b ) Range of projectile
= u²sin2θ / g
= 42² sin32 x 2 / g
= 42² sin64 / 9.8
= 161.8 m
c )
Max height = u² sin²32 / 2 g
= 42² sin²32 / 2x 9.8
= 25.27 m .
Which statements describe the types of energy emitted by the Sun? Check all that apply.
It emits most of its energy in gamma rays.
It emits all wavelengths in the electromagnetic spectrum.
It emits most of its energy as visible light.
Its peak wavelength is in the orange-yellow range.
It emits no X-rays or radio waves.
Its peak wavelength is in the yellow-green range.
The statement that describes the types of energy emitted by the Sun is that It emits all wavelengths in the electromagnetic spectrum, therefore the correct answer is option B.
What is electromagnetic radiation?Electromagnetic radiation is a type of energy radiation produced by the propagation of electromagnetic waves that are produced for natural as well as anthropogenic reasons.
As given in the problem we have to find out which statements describe the types of energy emitted by the Sun from the given list of options,
Thus, Sun emits all wavelengths in the electromagnetic spectrum, which means that option B is the appropriate response.
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What is the speed of the tip of the minute hand of a clock where the hand is of length 7cm?
Explanation:
Q1) What is the speed of the tip of the minute hand of a clock where the hand is of length 7cm?
Ans1) speed, v=st=2πrT=2×227×7×10-260×60=119×10-4=1.22×10-4m/s
Hope it helpsAn object is positioned in front of a concave mirror behind the center of curvature. Choose the ray diagram that shows
the proper positioning of the image.
Answer: it’s the diagram with a small tree on one side and a larger tree on the other side.
The ray diagram that shows the proper positioning of the image is: the first diagram, where the image is smaller than the object.
What is a concave mirror?A concave mirror also known as converging mirror is a type of curved or spherical mirror in which the outside surface is silvered and the inner surface is made to reflect.
The size and the nature of the image of this kind of mirror is relatively dependent on the position of the object with regards the mirror.
Analysis:
When the object is behind the centre of curvature, the image is seen to be real, inverted and smaller than the object.
So, the image of the concave mirror increases in size as the object gets closer to the centre of curvature and would be same size as the object at the centre of curvature.
In conclusion, the ray diagram that shows the proper positioning of the image is the first diagram.
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Which event demonstrates electromagnetic waves transferring energy?
Question 7 options:
An astronaut tapping two rocks together
A person diving in a swimming pool
An explosion causing a window to break
Sun heating a car sitting in a parking lot
Answer:
Sun heating a car sitting in a parking lot
Explanation:
The sun heating a car sitting in a parking lot is an example of electromagnetic waves transferring energy.
Electromagnetic waves are produced from the vibration between electric and magnetic fields. These waves can be propagated through vacuum with no particles inside of them. The sun produces electromagnetic radiation through the process of nuclear fusion. These radiations are used to warm the earth surface. The sun heating a car sitting a parking lot is one vivid example.Answer:
d
Explanation:
2.) Sally turns on the lamp in her bedroom. The lamp requires use of electrical
energy. Select two forms of energy that are present when the light-bulb is on.*
A.) Heat and force
B.) Motion and electrical
C.) Heat and light
D.) Force and sound
Answer:
c
Explanation:
The lamp lights up using electrical power, and so the light bulb heats up.
Answer:a
Explanation:
i took the test
A source of sound produces a note of 512 Hz in air at 17 degree celsius with wavelength 66.5 cm. Find the ratio of molar heat capacities at constant pressure to constant volume at NTP. Densities of air and mercury at NTP are 1.293 kg/m^3 and 13600 kg/m^3 respectively.
Answer:
a. 0.32 b. 1448 m/s
Explanation:
We know v ∝ √T where v = velocity of sound and T = absolute temperature.
Let v₁ = velocity of sound at 17°, v₁ = fλ where f = frequency of sound = 512 Hz and λ = 66.5 cm = 0.665 m
So, v₁ = fλ = 512 Hz × 0.665 m = 340.48 m/s
T₁ = 17 + 273 = 290 K
Let v₂ = velocity of sound in air at NTP = unknown and T₂ = temperature at NTP = 0°C + 273 = 273 K
Now v₁/v₂ = √T₁/√T₂
So, v₂ = (√T₂/√T₁)v₁
= [√(T₂/T₁)]v₁
substituting the values of the variables, we have
v₂ = [√(273 K/290 K)]340.48 m/s
v₂ = [√0.9413]340.48 m/s
v₂ = (0.9702)340.48 m/s
v₂ = 330.35 m/s
Also v = √(γP/ρ) where v = velocity of sound in air at NTP = 330.35 m/s, γ = ratio of molar heat capacities, P = pressure at NTP = 1.013 × 10⁵ Pa and ρ = density of air = 1.293 kg/m³
Since, v = √(γP/ρ)
making γ subject of the formula, we have
γ = v²ρ/P
substituting the values of the variables, we have
γ = (330.35 m/s)² × 1.293 kg/m³/1.013 × 10⁵ Pa
= 31975.36 kg/m²s² ÷ 1.013 × 10⁵ Pa
= 0.32
b. Speed of sound in mercury v₃ = √(B/ρ) where B = Bulk modulus of mercury = 28.5 × 10⁹ Pa and ρ = density of mercury = 13600 kg/m³
v₃ = √(B/ρ)
= √(28.5 × 10⁹ Pa/13600 kg/m³)
= √(28.5 × 10⁹ Pa/13.6 × 10³ kg/m³)
= √(2.096 × 10⁶) m/s
= 1.448 × 10³ m/s
= 1448 m/s
Bobby runs with an average velocity of 7.5 m/s over a straight-line distance of 90 meters. Calculate the time Bobby ran?
Answer:
12s
Explanation:
Given parameters:
Velocity = 7.5m/s
Distance = 90m
Unknown:
Time taken = ?
Solution:
Speed is the rate of distance traveled with time. It is mathematically expressed as;
Speed = [tex]\frac{distance}{time}[/tex]
Since the unknown is time;
Time = [tex]\frac{distance}{speed}[/tex]
Insert the parameters and solve;
Time = [tex]\frac{90}{7.5}[/tex] = 12s
Name the examples of compounds and their crystalline structure or shape.
Answer:
Water - Formula: H2O = Hydrogen2 + Oxygen. ...
Hydrogen Peroxide - Formula: H2O2 = Hydrogen2 + Oxygen2 ...
Salt - Formula: NaCl = Sodium + Chlorine. ...
Baking Soda - Formula: NaHCO3 = Sodium + Hydrogen + Carbon + Oxygen3 ...
Octane - Formula: C8H18 = Carbon8 + Hydrogen18
A disc 28 mm in radius rotates at a constant rate of 1.2 x10^5 rev/hr, about its central axis. Determine the tangential speed at a point 12mm from its center
Answer:
157m/s
Explanation:
We can convert 1.2 x10^5 rev/hr, to rad/secs for unit consistency
w=1.2×10^5rev/hr ×( 2π rad)/rev ×1 min/60sec
w=13083rad/sec
We can express the tangential speed inform of angular speed
Given speed at a point= 12mm12×10^-3m
V=wr
=13083rad/sec×12×10^-3
=157m/s
Hence the tangential speed at a point 12mm from its center is 157m/s
3. A coin is tossed vertically upward.
a. What happens to its velocity while it is in the air?
b. Does its acceleration increase, decrease, or remain constant while it is in the air?
Answer:
a. The initial velocity will decrease until it reaches its final velocity/maximum (which is 0).
b. The acceleration always remain constant.
The explosions that take place during a fireworks show are an example of which of the following?
Image of fireworks exploding in air
Chemical change
Chemical property
Physical change
Physical property
Answer:
I think it’s the 1rst one chemical change
Explanation:
Answer: A) Chemical Change
Explanation: When a firework explodes it realeses all of its chemical energy, thats why, (A)
is the correct answer
In a football game the running back is running up the field. He starts from rest and runs 4 seconds with an acceleration of 1.3m/s^2.
What is the magnitude of his displacement
Answer:
3.38m
Explanation:
Given parameters:
Time = 4s
Acceleration = 1.3m/s²
Unknown:
Magnitude of the displacement = ?
Solution:
The body starts at rest and the initial velocity is 0m/s. To solve this problem, we have to use the expression below;
S = Ut + [tex]\frac{1}{2}[/tex]at²
S = displacement
t is the time
a is the acceleration
U is the initial velocity
V is the final velocity
Insert the parameters and solve;
S = (0 x 4) + [tex]\frac{1}{2}[/tex] x 1.3² x 4 = 3.38m
27.0 mL to the nearest milliliter
Answer:
27.0 milliliters is the nearest mililiter so 27.0 is the answer
Explanation:
What does a barometer measure?
Answer:
Have a great day!
Explanation:
Barometers. A barometer is a scientific instrument used to measure atmospheric pressure, also called barometric pressure.
Answer:
atmospheric pressure
Explanation:
why did the rocky planets form in the inner section of the solar system
Answer:
Because it was too hot for volatile compounds (like water) to condense in the inner solar system, rocky planetesimals formed from compounds with high melting points, such as iron and rocky silicates
02
The ano ture of a converges
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21) The distance between crest and the adjacent trough of water wave is 3m They pass a given point
at a rate of 5m/sec. find
(a) the frequency?
(b) the speed of the water waves?
Answer:
1.67m
5m/s
Explanation:
Given parameters:
Wavelength of the wave = 3m
Speed of the wave = 5m/s
Unknown:
Frequency of the wave = ?
Speed of the water waves = ?
Solution:
The distance between crest and the adjacent trough of water waves is known as the wavelength of a wave.
To find the frequency ;
V = f∧
V is the speed of the wave
f is the frequency
∧ is the wavelength
Insert the parameters and find the frequency;
f = V/ ∧ = 5 / 3 = 1.67Hz
The rate at which the wave passed a given point is the speed of the wave and it is 5m/s
Can u generate energy by impact force?
Answer:
When thinking about the impact force of a falling object, you can calculate the energy of the object at its point of impact if you know the height from which it was dropped.
Explanation:
A satellite orbits earth with a mean altitude of 361 km. If the orbit is circular, what are the satellite's time period and speed?
Answer:
v = 7.69 x 10³ m/s = 7690 m/s
T = 5500 s = 91.67 min = 1.53 h
Explanation:
In order for the satellite to orbit the earth, the force of gravitation on satellite must be equal to the centripetal force acting on it:
[tex]F_{gravitation}= F_{centripetal}\\\\\frac{GM_{s} M_{E}}{r^2} = \frac{M_{s} v^2}{r}\\\\\frac{GM_{E}}{r} = v^2\\\\v = \sqrt{\frac{GM_{E}}{r} } \\\\[/tex]
where,
G = Universal Gravitational Constant = 6.67 x 10⁻¹¹ N.m²/kg²
Me = Mass of Earth = 5.97 x 10²⁴ kg
r = distance between the center of Earth and Satellite = Radius of Earth + Altitude = 6.371 x 10⁶ m + 0.361 x 10⁶ m = 6.732 x 10⁶ m
v = orbital speed = ?
Therefore,
[tex]v = \sqrt{\frac{(6.67 x 10^{-11}N.m^2/kg^2)(5.97 x 10^{24} kg)}{6.732 x 10^6 m} }\\\\[/tex]
v = 7.69 x 10³ m/s
For time period satellite completes one revolution around the earth. It means that the distance covered by satellite is equal to circumference of circle at the given altitude.
So, its orbital speed can be given as:
[tex]v = \frac{Circumference of Circle at Given Altitude}{T}\\\\v = \frac{2\pi r}{T}\\\\[/tex]
where,
T = Time Period of Satellite = ?
Therefore,
[tex]T = \frac{2\pi r}{v}\\\\T = \frac{(2\pi )(6.732 x 10^6 m}{7.69 x 10^3 m/s}\\\\[/tex]
T = 5500 s = 91.67 min = 1.53 h
Under what conditions does moving electric charge produce a magnetic force
in a copper wire?
A. Under any conditions
B. Only when the wire is connected to the magnet
C. Only when the wire is wrapped around an iron bar
D. Only when the wire is coiled
Answer:
I'm pretty sure that the answer is C. Hope this helps.
Explanation:
Answer:
Answer is A. Under any conditions
Explanation:
Just got it correct on A p e x
Bandura found that children who witnessed aggressive behavior being punished were far more likely to be aggressive than children who did not.
Please select the best answer from the choices provided
T
F
(Psychology)
Bandura's social learning theory, imitation, and observation are the two main ways that people pick up new skills. Bandura's theory encompasses more than just the notion that interaction with the environment leads directly to learning.
What Bandura children witnessed aggressive behavior?According to Bandura, hostility can also be learned indirectly through observational learning. According to the social learning theory, children learn through imitation.
An individual will internalize and replicate the aggressive behaviors of a role model in the future.
According to Bandura social learning theories, children pick up aggressive behaviors via watching others act aggressively and seeing how these actions are reinforced over time.
Therefore, it is false being punished were far more likely to be aggressive than children who did not.
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An elevator, in which a man is standing moving upward with a constant
speed of 10m/sec2. If a man drops a coin from a height of 2.5m. Find the time
taken by it to reach the oor of the elevation? g=9.8m/sec2
ANSWER
Lift frame :
Initial speed of the coin u=0 m/s
Acceleration a=9.8 m/s
2
Initial height of coin from the floor of elevator h=2.45 m
Time taken by coin to hit the floor T=
g
2H
⟹ T=
9.8
2×2.45
=
2
1
s
velocity of the lift (u₁) = 10 m/s
initial velocity of the coin (u₂) = 10 m/s
(the coin is also moving with the Elevator)
acceleration of the coin (a₂) = -9.8 m/s²
acceleration of the Elevator (a₁) = 0 m/s
Distance covered by the coin (s) = -2.5 m
__________________________________________________________
Relative Velocity and Acceleration:Relative velocity:
We will find the velocity and acceleration of the coin with respect to the lift since we are monitoring the motion of the coin
velocity of the coin with respect to the elevator (u₂₁) = u₂ - u₁
u₂₁ = 10 - 10
u₂₁ = 0m/s
Relative Acceleration:
acceleration of the coin with respect to the elevator (a₂₁) = a₂ - a₁
a₂₁ = -9.8 - 0
a₂₁ = -9.8
__________________________________________________________
Solving for the Time taken:From the second equation of motion, we know that:
s= ut + 1/2at₂
we can rewrite this equation in terms of relative motion:
s = u₂₁(t) + 1/2(a₁₂)t²
Notice that the time and the displacement are not relative, that's because displacement and time will remain the same no matter the frame of reference
replacing the known values in the equation:
-2.5 = (0)(t) + 1/2 (-9.8)(t²)
-2.5 = -4.9(t²)
dividing both sides by -4.9
t² = -2.5 / -4.9
t² = 25/49
t² = (5)² / (7)²
taking the square root of both the sides
t = 5/7 OR 0.71 seconds (approx)
Therefore, the coin will reach the floor of the Elevator in 0.71 seconds
A disrupted circuit in which the current bypasses its proper path is a(n) ________ circuit.
Answer:
short circuit
Explanation:
A disrupted circuit in which the current bypasses its proper path is a short circuit.
What is a Short circuit?A short circuit is an electrical circuit which allows the electric current to travel along an unintended and uninterrupted path with no or very low electrical impedance in the circuit. This results in an excessive current flow through the electric circuit.
A short circuit is a situation in which there is faulty connection or damaged wire that causes electric current to travel along the wrong route in the circuit with low or no resistance and damage an electrical device. This may cause serious damage, fire, or even small-scale explosions.
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At what incident angle, with respect to the normal to the interface, is light inside the crown glass completely polarized when reflected from water
Answer:
57°
Explanation:
Etienne Malus discovered the idea of polarization by reflection. If light is incident on a surface at an angle of 57°, the reflected ray is found to be plane polarized.
Hence, with respect to the normal to the interface, light incident at 57° is completely polarized.
Planets A and B have the same size, mass, and direction of travel, but planet
A is traveling through space at half the speed of planet B. Which statement
correctly explains the weight you would experience on each planet?
A. You would weigh the same on both planets because their masses
and the distance to their centers of gravity are the same.
O B. You would weigh the same on both planets because your mass
would adjust depending on the planet's speed.
O C. You would weigh less on planet B because it is traveling twice as
fast as planet A.
D. You would weigh more on planet B because it is traveling twice as
fast as planet A
A diffraction grating has rulings of 890 lines/mm. When white light is incident normally on the grating, what is the longest wavelength that forms an intensity maximum in the fifth order
Answer:
225nm
Explanation:
The Maxima of diffraction girating
dsin( θ)= m(λ)
Where θ)= angle between central axis and corresponding point
The wavelength is to corresponding sin( θ)
Then the maximum number of (λ) can be seen by setting sin( θ)= 1 then
d= m(λ)
At fifth order maximum m=1 then
d= 5(λ)
Where d= distance between the slit and with girating of 1/890rullig/mm
d= 1/890rullig/mm= 8.90×10^-6m
At maximum wavelength
d= 5(λ)
(λ)=5/d
= 8.90×10^-6m/5
=2.75*10^-7
= 275nm
Therefore, longest wavelength that forms an intensity maximum in the fifth order is 275nm