Purchase Solution

Rotating helicopter blades; bolt of lightning; radio waves; solar radiation; space flight

Not what you're looking for?

Ask Custom Question

1. A helicopter has blades of length 3.0m, rotating at 2.0rev/s about a central hub. If the vertical component of Earth's magnetic field is 5.0*10^-5T, what is the emf induced between the blade tip and the central hub?

2. A bolt of lightning depicted in a picture passes 200m from a 100-turn coil oriented as shown. If the current in the lighting bolt falls from 6.02*10^6A to zero in 10.5us, what is the average voltage induced in the coil? Assume that the distance to the center of the coil determines the average magnetic field at the coil's position. Treat the lighting bolt as a long, vertical wire. Here is the answer just need to know how to get it. ANSWER=115kV

3. An important news announcement is transmitted by radio waves to people who are 100km away, sitting next to their radios, and by sound waves to people sitting across the newsroom, 3.0m from the newscaster. Who receives the news first? Explain. Take the speed of sound in air to be 343m/s.

4. The intensity of solar radiation at the top of Earth's atmosphere is 1340W/m^3. Assuming that 60% of the incoming solar energy reaches Earth's surface and assuming that you absorb 50% of the incident energy, make an order-of-magnitude estimate of the amount of solar energy you absorb in a 60 min. sunbath.

5. A possible means of space flight is to place a perfectly reflecting aluminized sheet into Earth's orbit and to use the light from the Sun to push this solar sail. Suppose such a sail, of 6.00*10^4m^2 and mass 6000kg, is placed in orbit facing the Sun. a)What force is exerted on the sail? b) What is the sail's acceleration? c) How long does it take for this sail to reach the Moon, 3.84*10^8m away? Ignore all gravitational effects, and assume a solar intensity of 1340W/m^2. Hint[The radiation pressure by a reflected wave is given by 2(average power per unit area)/c.]
Again I have the answer but need to see how its done.
a)ANSWER=0.536N B)ANSWER=8.93*10^-5M/s^2 C)ANSWER=33.9DAYS

Attachments
Purchase this Solution
Solution Summary

With very detailed explanations and calculations, the problems are solved.

Solution Preview

1.) At any point on the blade at a distance r from the center of rotation:
v = w*r, where w = angular frequency = 2*pi*f
f= 2 rev/sec
Because induced emf: B*v*l
here v is varying from point to point, therefore emf due to each side of blade (i.e l/2 = 1.5 m):
e = integration(0 to l/2)[B*2*pi*f*r*dr]
the induced emf due to both sides will be either from tip to center or center to tip, i.e two emf's will act as parallel batteries of emf e = int(0 to l/2) [B*2*pi*f*r*dr]
=> e = 2*pi*f*B*(l^2/4)*/2= {pi*f*B*l^2}/4 =
=> e = pi* 2*5*10^(-5)*3^2 /4 = 0.71 mV Ans

2.) Sorry I'm not getting clear idea from the picture you have attached.
In the picture ...

Solution provided by:
Amrit Lal Ahuja, PhD (IP)
Education
  • BEng, Allahabad University, India
  • MSc , Pune University, India
  • PhD (IP), Pune University, India
Recent Feedback
  • " In question 2, you incorrectly add in the $3.00 dividend that was just paid to determine the value of the stock price using the dividend discount model. In question 4 response, it should have also been recognized that dividend discount models are not useful if any of the parameters used in the model are inaccurate. "
  • "feedback: fail to recognize the operating cash flow will not begin until the end of year 3."
  • "Answer was correct"
  • "Great thanks"
  • "Perfect solution..thank you"
Purchase this Solution
Free BrainMass Quizzes
Intro to the Physics Waves

Some short-answer questions involving the basic vocabulary of string, sound, and water waves.

Variables in Science Experiments

How well do you understand variables? Test your knowledge of independent (manipulated), dependent (responding), and controlled variables with this 10 question quiz.

The Moon

Test your knowledge of moon phases and movement.

Basic Physics

This quiz will test your knowledge about basic Physics.

Introduction to Nanotechnology/Nanomaterials

This quiz is for any area of science. Test yourself to see what knowledge of nanotechnology you have. This content will also make you familiar with basic concepts of nanotechnology.

View More Free Quizzes
Related BrainMass Solutions

  • Electromagnetic radiation and telescopes

    343669 Electromagnetic radiation and telescopes What do radio waves, infrared radiation, visible light, ultraviolet radiation, X-Rays and gamma rays have in common? How do they differ? Do astronomers look at visible light only?

  • Physics Astronomy: Electromagnetic Radiation

    The speed of all the EM radiations be same in the free space, hence as frequency increases, wavelength decreases. On the basis of increasing wavelength or decreasing frequency the EM radiations are classified from gamma rays to radio waves.

  • What Is and Is Not Torsion

    - helicopter blades normally rotating around - knees and arms bending Hello and thank you for posting your question to Brainmass.

  • Electromagnetic radiation and astronomers

    However, electromagnetic radiation exhibits a wide range of wave lengths, from radio waves kilometers long, to gamma radiation with a wavelength of few angstroms. In between we have the visible light spectrum.

  • Determining Inertia and Rotational Kinetic Energy

    283129 Determining Inertia and Rotational Kinetic Energy A helicopter has two blades (see figure), each of which has a mass of 220 kg and can be approximated as a thin rod of length 6.7 m. The blades are rotating at an angular speed of 55 rad/s.

  • The angular velocity of the rotating Pulsar using beeps.

    135093 The angular velocity of the rotating Pulsar using beeps A pulsar is a rapidly rotating neutron star that continuously emits a beam of radio waves in a searchlight manner.

  • Rotational inertia and kinetic energy of spinning blades

    17091 Inertia A helicopter has 3 blades, each of them are 5.20m long and has a mass of 220kg.(each blade has a mass of 220kg, not the sum of the 3) The rotor is rotating at 385 rev/min.

  • Radio Frequency Discharge versus Dielectric Barrier Discharge

    RFD: In the RFD concept, radio-frequency waves are applied to the gas. These waves have enough energy to excite the gas atoms to form an excimer gas.

  • Write a summary of the issues presented in this article. The

    458751 Write a summary of the issues presented in this article. The case is attached Wireless Radiation Frying Your Brains? Radio waves, microwaves, and infrared all belong to the Electromagnetic radiation spectrum.

View More Related Solutions