A car travels at 54 km/hr for first 20 secs , 36 km/hr for next 30 secs and finally 18 km/hr for next 10 secs. Find its average speed.
Two trains of length 250 m and 150 m are running in the same direction at a rate of 32 km/hr and 50 km/hr. How long will they take to cross each other?
A vehicle is acccelarating on a straight road. Its velocity at an instant is 30km/hr. After 2 sec ,it is 33.6 km/hr and after further 2sec it is 37.2 km/hr. Find the accelaration is m/sec.