Question

You are driving your car,and the traffic light ahead turns red. You apply the brake for 3.00s,and the velocity of the car decreases to +4.50m/s.The car's deceleration has a magnitude of 2.70m/s^2 during the time. What is the car's displacement.​

Answer 1

Question:-

You are driving your car,and the traffic light ahead turns red. You apply the brake for 3.00s,and the velocity of the car decreases to +4.50m/s.The car's deceleration has a magnitude of 2.70m/s^2 during the time. What is the car's displacement.

Answer:- 25.65

Given:-

• Applied a brake for 3 sec
• Velocity of the car decreases to 4.5m/s
• declaration of car is 2.7m/s^2

t = 3 sec , v = 4.5m/s , a = -2.7m/s^2

Formula:- v = u + at

s = ut + 1/2 at^2

v^2 - u^2 = 2as

To Find:-. u = ? , s = ?

Explanation-

v = u +at

4.5 = u + (-2.7) (3)

4.5 = u - 8.1

-u = -4.5 - 8.1

-u = -12.6 [ - and - will be cancelled]

u = 12.6

t = 3 sec , v = 4.5 m/s , a = -2.7m/s^2 , u = 12.6 m/s , s = ?

v^2 - u^2 = 2as

(4.5)^2. - ( 12.6 ) ^2 = 2 × -2.7 × s

20.25 - 158.76 = -5.4s

s = -138.51

-5.4

s = 25.65