Answer:
The acceleration of this helicopter is 

Step-by-step explanation:
 In this question the velocity changes from 30 m/sto 40 m/s in 5 seconds. 
Initial velocity u= 

Final velocity u= 

Time t= 
 
 
Acceleration is defined as the rate of change of velocity. It is given by the equation 

 =

= 
 
 
= 

 All moving bodies aren’t necessarily accelerated. To be identified as accelerating, a body should have its velocity changing. Thus a body in uniform motion is not accelerating since its velocity is constant.