Stopping distance given frictional force

[Chica1975]

Homework Statement

In an emergency stop on a level, dry concrete road, the magnitude of the friction force when sliding is approx 80% of the weight of the vehicle what is the stopping distance required for a vehicle traveling at 88km/h (24.444m/s). assume that all the wheels lock when the brakes are applied.

Homework Equations

to be honest i freaked out when I saw this question - i looked at my textbook but it really is useless.
is the frictional coefficient .20?

The Attempt at a Solution

I have no idea what to do
apparently the answer is 38m

 

[berkeman]

Homework Statement

In an emergency stop on a level, dry concrete road, the magnitude of the friction force when sliding is approx 80% of the weight of the vehicle what is the stopping distance required for a vehicle traveling at 88km/h (24.444m/s). assume that all the wheels lock when the brakes are applied.

Homework Equations

to be honest i freaked out when I saw this question - i looked at my textbook but it really is useless.
is the frictional coefficient .20?

The Attempt at a Solution

I have no idea what to do
apparently the answer is 38m

Not 0.2. Remember that the frictional force is F = mu * N, where in this case, N is the weight of the car. So what is mu?

Anyway, if the frictional force is constant (which it is in this problem), you use the kinematic equations of motion for constant accerleration (just like you use for gravity-related problems). What is the equation that relates the velocity to the applied acceleration (or deceleration in this case)?

 

[Chica1975]

I have no idea what mu is and N I don't have just that vehicle is traveling at 88km/h. I am ok with the kinematic equations when I have the numbers to plug in. I have no idea how to get the N for the weight of the vehicle just by being given that the frictional force is 80% the weight of the vehicle.

 

[Chica1975]

can someone please tell me how to do this? I have no idea how to workout the weight of the car. I need to hand this in. Without it being explained I really don't know what i am doing in the least.