How Many Revolutions Do Tires Make Before Stopping?

[mandy9008]

Homework Statement

A car initially traveling at 33.8 m/s undergoes a constant negative acceleration of magnitude 1.80 m/s2 after its brakes are applied. (a) How many revolutions does each tire make before the car comes to a stop, assuming the car does not skid and the tires have radii of 0.330 m? (b) What is the angular speed of the wheels when the car has traveled half the total distance?

The Attempt at a Solution

v²=vo² + aΔx
0= 33.8 m/s + 2(-1.8 m/s²)Δx
Δx=9.39
Δө=9.39 rad / 2π = 1.49 rev

 

[inky]

Homework Statement

A car initially traveling at 33.8 m/s undergoes a constant negative acceleration of magnitude 1.80 m/s2 after its brakes are applied. (a) How many revolutions does each tire make before the car comes to a stop, assuming the car does not skid and the tires have radii of 0.330 m? (b) What is the angular speed of the wheels when the car has traveled half the total distance?

The Attempt at a Solution

v²=vo² + aΔx
0= 33.8 m/s + 2(-1.8 m/s²)Δx
Δx=9.39
Δө=9.39 rad / 2π = 1.49 rev

You forgot to do square for v₀. So calculate again.