Question

a truck attained a velocity of 36km/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.