Question

The reaction time for an automobile driver is 0.5 s. If the automobile can be decelerated at 4m/s^2 , calculate the total distance travelled in coming to stop from an initial velocity of 30 km/hr , after a signal is observed.

Answer 1

-a = -4m/s^2
t = o.5 sec
s =?
v = om/s
u = 30 km/ hr = 8.33 m/s

S = ut + 1/2 at^2
= 8.33 × 0.5 + 1/2 × -4 × (0.5 )^2
= 4.165 - 2 × 0.25
= 4.165 - 0.5
= 3.665