A wind turbine is initially spinning at a constant angular speed. As the wind's strength gradually increases, the turbine experiences a constant angular acceleration 0.116 rad/s2. After making 2870 revolutions, its angular speed is 124 rad/s. (a) What is the initial angular velocity of the turbine? (b) How much time elapses while the turbine is speeding up?
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4. A boy stands on a diving board and tosses a stone into a swimming pool. The stone is thrown from a height of 2.8 m above the water surface with a velocity of 5.6 m/s at 72 degrees above the horizontal.
a) First determine the time it is airborne. (I got 1.48 sec)
b) Now find its impact velocity. (Vx=2 m/s and Vy=9.17 m/s)
As the stone impacts the water, it instantly slows down to half its previous velocity, and maintains that velocity (both speed and direction) as it sinks to the bottom of the pool, which is 4.0 m deep.
c) Find the time it takes to reach the bottom. (1.93 sec)
Bonus +3 What is the total horizontal displacement of the stone over its entire trip? I dont know how to do this one
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how does an intensifying screen work and what does it do? The goal is to be able to understand what the question is asking, be able to understand the answer, and also use your own words as much as possible
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A single-turn square loop of wire, 2.00 cm on each edge, carries a clockwise current of 0.160 A. The loop is inside a solenoid, with the plane of the loop perpendicular to the magnetic field of the solenoid. The solenoid has 30.0 turns/cm and carries a clockwise current of 15.0 A.
(1) Find the force on each side of the loop.
magnitude:____________________uN
direction: a) the force is zero b) directed towards the center c) directed away from the center
(2) Find the magnitude of the torque acting on the loop.
___________________ N
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Understand and be able to state the followings:
• Archimedes’ Principle• Pascal’s Principle
• Bernoulli’s Principle• Hooke’s Law
• Newton’s Law of Cooling
• First Law of Thermodynamics
• Second Law of Thermodynamics
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A 1.0-cm-tall object is 100 cm from a screen. A diverging lens with focal length -20 cm is 20 cm in front of the object.
a. What is the focal length of a second lens that will produce a well-focused, 2.0-cm-tall image on the screen?
b. What is the distance from the screen of the second lens?
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You take your trusty 120 turn solenoid, with 20 cm diameter and spin it at a rate of 10 times per second in a magnetic field that you have constructed with two gigantic neodymium magnets, creating a uniform magnetic field. You are spinning the solenoid so that its rotation axis is perpendicular to the magnetic field direction.
a) What field strength do you need to create a peak emf voltage of 150 V? (Hint: use flux as a function of angle.)
b) What orientation must the solenoid be in to achieve peak emf?
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Can someone please explain rotational motion?
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Two point charges 1.8 cm apart have an electric potential energy -180 μJ . The total charge is 31 nC
What are the two charges? Answer in nC
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A 32.0-μF capacitor is connected to a 53.0-Ω resistor and a generator whose rms output is 30.0 V at 60.0 Hz.
(a) Find the rms current in the circuit.
______ A
(b) Find the rms voltage drop across the resistor.
______ V
(c) Find the rms voltage drop across the capacitor.
_______ V
(d) Find the phase angle for the circuit.
The voltage _______ leads ahead of lags behind the current by
_____°.
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An argon laser that has a wavelength of 455 nm shines on a double-slit apparatus, which produces an interference pattern on a screen that is 10.0 m away from the slits. The slit separation distance is 70.0 μm. (a) How many bright fringes are there on the screen within an angle of ±1° relative to the central axis? (b) How many dark fringes are there on the screen within an angle of ±2° relative to the central axis? Be careful to count all the fringes.
answer: a) 5 b)8, please explain how to get these correct answers.
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Tipler6 24.P.053.soln.
A 90-pF capacitor and a 360-pF capacitor are both charged to 2.50 kV. They are then disconnected from the voltage source and are connected together, positive plate to negative plate and negative plate to positive plate.
(a) Find the resulting potential difference across each capacitor.
| V90 pF | = kV |
| V360 pF | = kV |
(b) Find the energy lost when the connections are made.
µJ
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Calculate the gauge pressure (in Pa) inside a soap bubble 2.4 cm in radius using the surface tension γ = 0.022 N/m for the solution. Enter a number with one digit behind the decimal point.
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A cannon fires a cannon ball at an angle of θ0 = 30.0° above the horizontal axis. The initial speed of the ball is 395 m/s . Ignore air resistance for all calculations.
A) Find the maximum height h that the ball attains.
B) Find the horizontal distance (range) R the cannon ball would travel given the above (the same as for Part A) conditions.
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very massive black holes with masses of Billions of solar masses are primarily formed how?
| A. |
They have formed from a collapse of a giant gas cloud |
|
| B. |
They are primarily formed through accretion of matter |
|
| C. |
The are primarily formed through merging of smaller black holes. |
|
| D. |
They have been formed during the Big Bang |
What properties of a Black Hole can you determine theoretically
| 1. |
Mass, magnetic field, and spin |
|
| 2. |
Mass, Spin, and electric charge |
|
| 3. |
Mass, chemical composition, Spin |
|
| 4. |
Spin, magnetic field, and chemical composition. |
What can you say about Hawking radiation?
| 1. |
Hawking radiation can only be seen from super-massive Black holes |
|
| 2. |
The more massive the black hole the later the luminosity through Hawking radiation |
|
| 3. |
The smaller the mass of the black hole the more luminous is the Hawking radiation |
|
| 4. |
You can see Hawking radiation only n the infrared |
What is the engine in an AGN
| 1. |
Splitting of Uranium atoms |
|
| 2. |
Nuclear fusion of Carbon |
|
| 3. |
An Accretion Disk around a central Black Hole |
|
| 4. |
Hawking radiation |
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