Question

After the 1114 kg jet-powered car Spirit of America went out of control during a test drive at Bonneville Salt Flats, Utah, it left skid marks about 6.7 km long.
1. If the car had an initial speed of 425 km/h, estimate the coefficient of kinetic friction. The acceleration of gravity is 9.81 m/s^2 .

Answer 1

Answer:

μ = 0.104

Explanation:

Given that

m = 1114 kg

s= 6.7 km = 670 m

Initial velocity ,u = 425 km/h

1 km/h= 0.27 m/s

u= 118.056 m/s

The final velocity of car ,v= 0 m/s

We know that

v² = u² + 2 a s

a=Acceleration

Now by putting the values

0² = 118.056² + 2 x a  x 670

a=-\dfrac{118.056^2}{2\times 670} m/s^2

a= - 10.4 m/s²

The acceleration also given as

a = - μ g            ( fr = m μ g  = - m a)

10.4 = 10 x μ         ( take g= 10 m/s²)

μ = 0.104

Therefore the coefficient of kinetic friction will be 0.104 .