# Homework Help: 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.