A driver starts from rest on a straight test track that has markers every 0.14 km. The driver presses on the accelerator and for the entire period of the test holds the car at constant acceleration. The car passes the 0.14 km post at 8.0 s after starting the test.
(a) What was the car's acceleration?
(b) What was the car's speed as it passed the 0.14 km post?

(A) Constant acceleration will be

(B) Velocity of the car when it passes 0.14 km is 20.349 m/sec

Explanation:

It is given that driver starts from rest so initial velocity of the driver u = 0 m/sec

Distance traveled s = 0.14 km = 140 m

Time taken to cross 0.14 km is 8 sec

So time taken t = 8 sec

(A) From second equation of motion

So

(B) From third equation of motion

v = 20.349 m/sec

So speed of the car when it passed 0.14 km is 20.349 m/sec

measuring things 1 litre of water