Another Time Dilation Question (1 Viewer)

[TeaYarn]

Alpha Centauri is 4.5 light years from earth. Imagine a spaceship able to fly at 0.9c. How long would it take to get there as observed by the pilot, and by mission control on earth?

I understand that v=0.9c and c=3x10^8
But how do you work out what T or To is by using the 4.5 light years away? Otherwise you have two unknowns?
Also how would you then complete the question?

Thanks

 

[strawberrye]

4.5 light years is a measure of distance/length, it is not time, to calculate the time, basically you have 4.5/0.9 to get the time using the formula time=distance/speed.

 

[bokat]

For mission control, it is exactly like you have a car moving at 100 km/hr, from Sydney to Canberra ( 300 km away) .
The time for this trip is time=distance/speed t=300/100 or 3 hours.
In the same way t=4.5/0.9 which gives 5 years for mission control. ( If distance is in light year and speed is in speed of light, then the time will be in years).

For the people on board the time will be shorter (time slows down on the board) so multiply the time for mission control by sqrt(1-(v/c)^2)
to get 2.18 years.

Reza Bokat,
Cambridge Coaching