Constant acceleration of hockey puck

[anna_chem]

Homework Statement

A hockey puck sliding on a frozen lake comes to rest after traveling 249 m. If its initial velocity is 4.5 m/s, what is its acceleration if that acceleration is assumed constant?

Homework Equations

V(t)= v(initial) + at
d= v(initial)*t + .5at^2

The Attempt at a Solution

V(t)= 4.5 m/s + at or 249 m= 4.5 m/s*t + at^2

I'm confused as to where to go from here. How can I go about finding t, so that I can find a? Or am I trying to go about it wrong?

 

[rock.freak667]

Homework Statement

A hockey puck sliding on a frozen lake comes to rest after traveling 249 m. If its initial velocity is 4.5 m/s, what is its acceleration if that acceleration is assumed constant?

Homework Equations

V(t)= v(initial) + at
d= v(initial)*t + .5at^2

The Attempt at a Solution

V(t)= 4.5 m/s + at or 249 m= 4.5 m/s*t + at^2

I'm confused as to where to go from here. How can I go about finding t, so that I can find a? Or am I trying to go about it wrong?

Yes, that is one way, but you are missing time, so that equation can't be used.
We need an equation with initial,final velocity,displacement and acceleration

like this one

v²=u²+2ad

 

[anna_chem]

Thanks for the quick response. So, given that initial velocity is 4.5 m/s and final velocity is 0, then:
4.5^2=0+498a thus a=.0407 m/s^2
Does that look correct?

 

[rock.freak667]

Thanks for the quick response. So, given that initial velocity is 4.5 m/s and final velocity is 0, then:
4.5^2=0+498a thus a=.0407 m/s^2
Does that look correct?

v²=u²+2ad

v=final velocity

u=initial velocity.