Kinematics - Can the car avoid the moose

[k790]

Homework Statement

You are driving along the road at 80 km/h (22m/s) when you see a moose 50.0 m in front of your car. Your reaction time is 0.40 s, and when you finally hit the brakes your car decelerates at a rate of -6.4 m/s2.

a) Will your car stop in time to avoid the moose?

b) If the road is wet and your car decelerates at a rate of 4.8 m/s2, what will happen?

Homework Equations

d = ½( vo + vf) t
at = vf– vo
d = vot + ½ at2
vo2= vf2 + 2ad

The Attempt at a Solution

Ive tried using the equations, I know vi= 22m/s then vo=Om/s but I think I am making some sort of mistake, can someone push me in the right direction?

 

[noleguy33]

You need to calculate how far you will travel during your reaction time, using your distance function. Then calculate how long it will take to stop using your velocity function. Take that time and plug it into your distance function and add the reaction time distance to the stopping distance and see if it's greater than 50 meters.