Advise how volta specifically can patent its its (first in the world and novel) clean energy engine.

Volta specifically can patent in clean energy engine novel in as it has to fulfill the three criteria.
1. It should be useful.
2. It should be unique or new in the market.
3. It should be non-obvious which is easily recognizable. 
It is easy to understand. The three qualities are being possessed by novel VOLTa as the concept is very new and it will be very beneficial for the world or public.

The car would move to the right with 150 n of force. the 150 n of force from friction and air resistance slows the car from moving to the right with 300 n of force.

The answer is trial 3.