Calculating Time for a 90 Degree Turn in Circular Motion

[billu77]

Homework Statement

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?

Homework Equations

tangential acceleration = final velocity - initial velocity/time

The Attempt at a Solution

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

 

[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?

 

[rl.bhat]

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

 

[billu77]

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

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

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

thanks

 

[paul232]

That T= 2LaTeX Code: \\pi r/v is the time it needs to cover a full circle (360*)
So what's the time to cover 1/4 360*?

Thats time=T/4 = 1/4* 2πR/v.