Circular motion plane problem

1. Nov 10, 2009

billu77

1. The problem statement, all variables and given/known data

A pilot makes a turn of radius 50.0 meters at a speed of 26.0m/sec. How long will it take him to make a 90 degree turn?

2. Relevant equations

tangential acceleration = final velocity - initial velocity/time

3. The attempt at a solution

tangential acceleration = final velocity - 26/t
stuck at this point...unable to find final velocity from here???

2. Nov 10, 2009

ideasrule

You actually don't need that equation. How much distance does he have to cover to turn 90 degrees? How fast is he turning? (Hint: it's 26.0 m/s.) How much time does it take?

3. Nov 10, 2009

rl.bhat

Since speed is constant, time = 1/4* 2πR/v.

4. Nov 11, 2009

billu77

thanks...could u please explain how u got to that formula.
the one I have in book is:

T= 2$$\pi$$r/v

thanks

5. Nov 11, 2009

paul232

That T= 2LaTeX Code: \\pi r/v is the time it needs to cover a full circle (360*)
So whats the time to cover 1/4 360*?

Thats time=T/4 = 1/4* 2πR/v.