Motion with constant acceleration

[Faka]

The human body can survive an acceleration trauma incident (sudden stop) if the magnitude of the acceleration is less than 250 m/s². If you are in an automobile accident with an initial speed of 150 km/h (65 mi/h) and you are stopped by an airbag that inflates from the dashboard, over what distance must the airbag stop you from you to survive the crash?

Can somebody help me to solve this exercise?
How do I start?

 

[tiny-tim]

Welcome to PF!

Hi Faka! Welcome to PF!

You need to find the distance in which that acceleration will bring you to rest from that speed.

Use one of the standard https://www.physicsforums.com/library.php?do=view_item&itemid=204" equations.

 

[Galron]

Completely off topic but at one time we believed that we would not survive any speed over 40mph at any acceleration magnitude.

And now I will shut up.

 

[Faka]

Hi Faka! Welcome to PF!

You need to find the distance in which that acceleration will bring you to rest from that speed.

Use one of the standard https://www.physicsforums.com/library.php?do=view_item&itemid=204" equations.

Thank you..
Is it right that I can use this equation:
s = u*t+1/2*a*t^2

Could you maybe show me how to solve it?

 

[tiny-tim]

Hi Faka!

(try using the X² icon just above the Reply box )

Is it right that I can use this equation:
s = u*t+1/2*a*t^2

Nope!

(you don't know what t is, do you? )

Try one of the other standard https://www.physicsforums.com/library.php?do=view_item&itemid=204"equations. ​

 

[Faka]

Hi Faka!

(try using the X² icon just above the Reply box )


Nope!

(you don't know what t is, do you? )

Try one of the other standard https://www.physicsforums.com/library.php?do=view_item&itemid=204"equations. ​

No, I don't know what time, t is.
I can use this equation: v^2 = u^2 + 2*a*s

 

[tiny-tim]

Yup!

(You know u and v and a, and you want to find s, so you use the equation that doesn't have t. )

So s = … ? ​