A driver of a car moving with speed 90km/h saw a child on the road 25m ahead of him .he jammed on the brake and bought the car to rest and retradation of the car

Complete question :

A driver of a car moving with speed 90km/h saw a child on the road 25m ahead of him .he jammed on the brake and bought the car to rest. Calculate the time taken to bring the car to rest and retradation of the car.

t = 2 seconds ; retradation = - 12.5 m/s²

Explanation:

Given that :

Final velocity v = 0

Initial Velocity u = 90 km /hr = (90 * 1000)m / 3600s = 90000m/3600s = 25m/s

Distance = 25 m

Using the relation :

v² = u² + 2aS

where, S = distance covered a = retradation

0 = 25² + 2a(25)

0 = 625 + 50a

50a = - 625

a = - 12.5 m/s²

Time taken (t) :

Using :

v = u + at

0 = 25 + (-12.5 * t)

0 = 25 - 12.5t

12.5t = 25

t = 25 / 12.5

t = 2 seconds

        i'm fairly sure that the correct answers are 2 and 3.

        i used both my knowledge of world history and the process of elimination to obtain these answers. option 1 cannot be a possible selection because the mandate of heaven belongs to ancient chinese philosophical belief. option 4 sounds like it would benefit the region than detriment it. however, both 2 and 3 explain a potential reason for what could have contributed to the fall of the roman empire.

      hope this ! if i were you, i'd get a second opinion, because i haven't taken this course for a year. best of luck!

***websites that me understand the curriculum better last year are and ***