ANSWER
Power stroke
EXPLANATION
At the power stroke stage, the piston is forced to move down by the expanding gases as both intake valve and exhaust valve are closed.
A spark from the spark plug contributes to ignition of the compressed fuel air mixture to released energy to perform work.
"Work done by a constant force on an object is the product of the force and the distance moved by the object in the direction of the force" -textbook
There is work done ONLY if the direction of the force and the direction the item is moving are the same. In figure A, the direction of the force (the lifting) is upwards (defying gravity), and the book is moving upwards, so work is done. In figure B, the force is still moving upwards (the person is carrying the books) but the book is moving to the right, so there is NO work done.
Answer:
The correct answer is option B.
Explanation:
Moles of 
= 40 mol
Moles of NaOH = 48 mol
According to reaction, 3 moles of NaOH reacts with 2 moles
Then ,48 moles of NaOH will reacts with:
of
Then ,40 moles of 
will reacts with:
of NaOH
As we can see that 48 moles of sodium will completey react with 32 moles of nitrogen tribromide.
Moles left after reaction = 40 mol - 32 mol = 8 mol
Hence, the is an excessive reagent.
The spinal cord is part of the central nervous system
