A bus is moving with the velocity of 72km/he has acceleration 0.5m/².How long will it take to gain the velocity of 30 m/s?

First km/h to m/s:

m/s = km/h / 3.6

m/s = 72 / 3.6

m/s = 20

Now, use the formula:

Vf = Vo + at

Clear t:

t = (Vf - Vo) / a

Replace:

t = (30 m/s - 20 m/s) / 0.5 m/s²

Resolving:

t = 10 m/s / 0.5 m/s²

t = 20 s

It will take 20 seconds.

sonar - device which is used to find the submit submarines, sankalp ship. sonar waves consists of a transmitter and detector which are installed in the observation centre on board of a ship. the ultrasonic waves are sent into the sea at high frequency about 1000 khz in all direction.