Question

A truck attained a velocity of 36 km/hr in 10 sec just after the start. It takes 20 sec to stop. Calculate Acceleration in both cases

Answer 1

CASE 1:


Initial velocity, u = 0m/s

Final velocity, v = 36 km/hr = 10 m/s

Time, t = 10 s


Acceleration, a = (v - u) / t

∴a = (10 - 0) / 10

     = 10/10

∴a = 1 m/s²


Thus, acceleration of the truck is 1 m/s².


CASE 2:-


Initial velocity, u = 36 km/h = 10 m/s

Final velocity, v = 0 m/s

Time, t = 20 s


Acceleration, a = (v - u) / t

∴a = (0 - 10) / 20

     = -10/20

∴a = - 0.5 m/s²


Thus, acceleration of the truck is -0.5 m/s². The negative sign indicates retardation.