Edexcel PHYSICS Doubts

[YU-GI-OH!]

Why do aircraft take off and land into the wind

[Malak]

Why do aircraft take off and land into the wind

Is that the question? 

Check this, might be helpful: http://answers.yahoo.com/question/index?qid=20080831193525AASbJXE

[Banana]

Why do aircraft take off and land into the wind

Thats to ensure the polishing of the plane isn't ruined  

Check out ang3l's link  

[YU-GI-OH!]

If someone coasts from a greater speed than before, why would the deceleration be greater?
Thanks in advance

[astarmathsandphysics]

Aircraft takes off in the wind becuase lift depends on air speed relative to aircraft - if this is greater (because aircraft is moving into the wind) this relative speed and lift are greater.
Aircraft land into the wind becuase it is an aid to braking.

[astarmathsandphysics]

If someone coasts from a greater speed than before, why would the deceleration be greater?

Don't understand this. Please expand.

[The Golden Girl =D]

If someone coasts from a greater speed than before, why would the deceleration be greater?
Thanks in advance

Can you give me a link to the paper or perhaps write down the Whole Questions , it'll make it easier for us to answer =]

[YU-GI-OH!]

I have attached the question below. It's part 3 that I am stuck on 

[astarmathsandphysics]

Waiting for it to print on my very slow printer.

[astarmathsandphysics]

Air resistance increases with speed

[The Golden Girl =D]

Omega (Angular velocity) = 2 pie / T

T = 600 revolutions per minute.

Omega at the end is supposed to be about 63 rads^-1

I know this is Math , but I just can't seem to get the answer =,=

Thanks =]

[Banana]

Omega (Angular velocity) = 2 pie / T

T = 600 revolutions per minute.

Omega at the end is supposed to be about 63 rads^-1

I know this is Math , but I just can't seem to get the answer =,=

Thanks =]

w = 2pi / T

T is the period (time taken for one rotation) SO for 600 rpm each rotation takes 60/600 seconds = 0.1 sec
Substitute into the equation:

w= 2pi / (0.10) = 63 rad s-1 as the question says

[The Golden Girl =D]

w = 2pi / T

T is the period (rotations in one second) SO for 600 rpm there will be 600/60 revolitions per second( the period)

Substitute into the equation:

w= 2pi / (10) = 0.63 rad s-1

So basically it isn't 63 but 0.63  

In the Question it says it's about 63 though.  and isn't 600 supposed to be multiplied by 60 ?  


Another Question ,

Q. The average wind speed in the UK is 5.8 m s–1, which results in an actual average power output of 100W. Discuss whether it would be better for the environment to replace some filament light bulbs with low energy bulbs than to use this turbine. Assume each filament light bulb is rated at 100W and each low energy bulb is rated at 11 W.

Answer. The 100 W is an average over the whole day. Most households would use light bulbs for 6 hours a day in no more than 4 rooms, so this would mean no other energy was needed for lighting. 4 low energy bulbs would be 44 W for 6 each hours so would require energy from the National grid.

I don't get it.

Thanks =]

[The Golden Girl =D]

w = 2pi / T

T is the period (time taken for one rotation) SO for 600 rpm each rotation takes 60/600 seconds = 0.1 sec
Substitute into the equation:

w= 2pi / (0.10) = 63 rad s-1 as the question says

Today my brain is BLANK  so hmm why did you divide 60 by 600 ?

Explain it in details please 

[Banana]

Today my brain is BLANK  so hmm why did you divide 60 by 600 ?

Explain it in details please 

Okies....

Period is the time taken for one rotation..

Using proportion:

            Revolutions                            Time

               600-------------------> 1 minute =60 seconds

                 1 -------------------->       T seconds

Cross multiply:   600T = 60

                    Therefore, T = 60/600 = 0.1 seconds

This is the period!

All you have to do now is substitute into the equation: w= 2pi/ T

Voila!!