A car moves with constant acceieration of - 0. s m/s? on a straight portion of the road. Att - 0s the car has a velocity of 69 mph, how far does the car travels until its speed is reduced to haif? Select one: a. 1.12 km o b. 0.71 km c. 3.57 km d. 1.02 km

option (b) 0.71 km

Explanation:

Given:

Initial speed of the car, v = 69 mph = 69 * 0.44704 m/s = 30.84 m/s

final speed of the car, u = half the initial speed = 30.84 m/s / 2 = 15.42 m/s

acceleration, a = - 0.5 m/s²

Now,

from the Newton's equation of motion, we have

v² - u² = 2as

where, s is the distance traveled

on substituting the respective values, we have

30.84² - 15.42² = 2 * (-0.5) * s

713.329 = - 1 * s

or

s = 713.329 m (since the distance cannot be negative)

or

s = 0.713 km

hence,

the correct answer is option (b) 0.71 km