A car moving with a speed of 90km/hr was brought to rest by the application of the brakes in 1Os. How far did the car travel after the brakes were applied?

John Perolski
August 07, 2023

Physics Jamb, Waec, Neco Past Questions & Answers on Speed, Velocity and Acceleration

QUESTIONS 17. A car moving with a speed of 90km/hr was brought to rest by the application of the brakes in 1Os. How far did the car travel after the brakes were applied?

A. 125m B. 150m C. 250m D. 15km JAMB 1990 Ans;  125m


SOLUTIONS

Speed or Velocity v = 90km/hr = 90 x 1000m/60x60 = 90000/3600

V= 900/36 or v = 25m/s

Acceleration a = ? 

But a = v/ t 

a = 25/10 

a = 2.5m/s²

Time t = 10s

Distance s = ?


Applying second equation of motion 


S = ut + ½ at²

S = 0 x 10 + ½ x 2.5 x 10²

S = 0 + ½ x 2.5 x 100

S = 0 + 2.5 x 100/2

S = 0 + 250/2

S = 125m