Kinematic Equation Problem using Velocity & Distance

[dlang]

Hey guys, I'm confused on this problem: It is a typical sunny day. Assume your reaction
time is 0.50 s and the acceleration of your car is –8.2 m/s2. What is the no-skid stopping distance when the car’s speed is initially 26.9 m/s?

Homework Statement

a=-8.2 m/s^2
v0=26.9 m/s
v=0
t=0.50s
d=?

Homework Equations

d=v0(t) +1/2a(t^2)
v^2=v0^2+2ad

The Attempt at a Solution

So I tried using the v^2=v0^2+2ad and got 44.12 m. However, the answer is 57.57. What did I do wrong? Thanks!

 

[SammyS]

Hey guys, I'm confused on this problem: It is a typical sunny day. Assume your reaction
time is 0.50 s and the acceleration of your car is –8.2 m/s2. What is the no-skid stopping distance when the car’s speed is initially 26.9 m/s?

Homework Statement

a=-8.2 m/s^2
v0=26.9 m/s
v=0
t=0.50s
d=?

Homework Equations

d=v0(t) +1/2a(t^2)
v^2=v0^2+2ad

The Attempt at a Solution

So I tried using the v^2=v0^2+2ad and got 44.12 m. However, the answer is 57.57. What did I do wrong? Thanks!

Hello dlang. Welcome to PF !

Show detail regarding how you used the equations you gave.

d = v₀(t) +(1/2)a(t²)
v² = v₀²+2ad​

 

[Orodruin]

Hey guys, I'm confused on this problem: It is a typical sunny day. Assume your reaction
time is 0.50 s and the acceleration of your car is –8.2 m/s2. What is the no-skid stopping distance when the car’s speed is initially 26.9 m/s?

Homework Statement

a=-8.2 m/s^2
v0=26.9 m/s
v=0
t=0.50s
d=?

Homework Equations

d=v0(t) +1/2a(t^2)
v^2=v0^2+2ad

The Attempt at a Solution

So I tried using the v^2=v0^2+2ad and got 44.12 m. However, the answer is 57.57. What did I do wrong? Thanks!

What you have used is the formula for motion under constant acceleration which is true only after you have reacted. What about the distance traveled during your reaction time?