Answer : 
Explanation :
It is given that,
Mass of the engine, m = 30 kg
Thrust is equivalent to the force acting perpendicularly and it is F = 300 N
According to Newton's second law of motion :

a is the acceleration of the engine.



So, the acceleration of the engine is
.
Hence, this is the required solution.
$0.60
90 mins is 1.5 hrs
5 kW × 1.5 = 7.5 kWh
7.5 kWh × $0.08 = $0.60
Through refraction , it bends as it passes into a solid object