- #1

miniradman

- 196

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## Homework Statement

A Helicopter with blades that span 10.7m across is operating in an area where the Earth's magnetic field is 5.85 x 10

^{-5}T at an angle of 66

^{o}to the horizontal. Prior to takeoff the rotor blades are moving at 375rpm in a clockwise direction when viewed from the ground.

It is found that the motion of the blades causes a voltage difference within them.

Helicoper's Blade Span = 10.7 meters

Earth's magnetic field = 5.85 T x 10

^{-5}at angle of 66

^{o}to the horizontal

Rate of blades = 375rpm

## Homework Equations

a) which parts of the rotor blades are positive and negative (don't know what it refers to)

b) Calculate the verticle component at this point

c) Calculate the total flux enclosed in the area swept out by the blades

d) What would be the maximum EMF induced in the blades

## The Attempt at a Solution

B)

(sin 24)/ 1 = FV/5.85 x 10

^{-5}

FV = (Sin 24) x 5.85x

^{-5}

= 2.37 x 10

^{-5}

:. The verticle component is 2.37

^{-5}

*Converted rpm to speed = 210.094 m/s*

c)

*MAGNETIC FLUX*

area of a circle

[itex]\varphi[/itex] = BA

= 2.37 x 10[itex]^{}-5[/itex] x ([itex]\pi[/itex] x 5.35[itex]^{}2[/itex])

= 0.039 WD

d)

V= LvB

= 10.7 x 210.0.94 x 2.37 x 10[itex]^{}-5[/itex]

= 5.3277

It it all good?