Motion at Constant Acceleration Question 2

[Adrianna]

Homework Statement

A light plane must reach a speed of 33 m/s for takeoff. How long a runway is needed if the (constant) acceleration is 3.0m/s^2?

Homework Equations

I looked at the Kinematics Equations and tried to re-arrange them to be able to find the distance with what I was given.

The Attempt at a Solution

I am not sure how to start it, this is always my problem I can't seem to figure out what formula to use.

 

[rock.freak667]

Homework Statement

A light plane must reach a speed of 33 m/s for takeoff. How long a runway is needed if the (constant) acceleration is 3.0m/s^2?

The Attempt at a Solution

I am not sure how to start it, this is always my problem I can't seem to figure out what formula to use.

You have a final velocity, an initial velocity (the plane should be at rest) and an acceleration. You want to find a displacement.

Which of the kinematic equation contains those 4 quantities?

 

[Adrianna]

vf^2 = Vi^2 +2ad...?

 

[rock.freak667]

vf^2 = Vi^2 +2ad...?

So when you use that, what do you get for 'd'?

 

[jasper10]

v^2 = 0 * 2as
where v is final velocity, a is acceleration and s is the distance

 

[Adrianna]

I got 1.8 m/s and that's the right answer thanks so much for the help

 

[rock.freak667]

I got 1.8 m/s and that's the right answer thanks so much for the help

you mean you got 1.8m. m/s are the units for velocity.