Question

You are driving your car and the traffic light ahead turns red.You apply the breaks for 3s and the velocity of the car decreasesto 4.5 m/s . If the cars deceleration has a magnitude of 2.7m/s^2,what is the car's displacement during this time?

Answer 1

Answer:

The car's displacement during this time is 25.65 meters.

Explanation:

Given that,

Final velocity of the car, v = 4.5 m/s

Deceleration of the car, $a=-2.7\ m/s^2$

Let u is the initial speed of the car. It is given by :

$v=u+at$

$u=v-at$

$u=4.5-(-2.7)\times 3$

u = 12.6 m/s

Let d is the car's displacement during this time. It can be calculated using second equation of motion as :

$d=ut+\dfrac{1}{2}at^2$

$d=12.6\times 3+\dfrac{1}{2}\times (-2.7)\times 3^2$

d = 25.65 meters

So, the car's displacement during this time is 25.65 meters. Hence, this is the required solution.