Apilot increases the take off speed of a jet uniformly from 10 km/hr to 140km/hr in 50 seconds. what is the rate of acceleration?

Acceleration  =  (change in speed) / (time for the change)

Change in speed = (speed at the end) - (speed at the beginning)

                            =  (140 km/hr)  -  (10 km/hr)   =   130 km/hr

Time for the change  =  50 sec

Acceleration  =  (130 km/hr) / (50 sec)   =   2.6 km/hr per second.

To convert to more familiar units:

             (2.6 km/hr-sec) x (1000 m/km) x (1 hr/3600 sec)

         =  (2.6 x 1000 x 1) / (3600)         km-m-hr / hr-sec-km-sec        

         =     0.722  m/s²   (about 0.074 of a G)