A pilot 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)