Answer:
A. Speed
Explanation:
Speed is the magnitude of velocity, which is given in the question. Velocity is a vector quantity and therefore has both a magnitude and a direction. Only the former is implied in the question.
Answer:
5235.84 kg
Explanation:
There is one theorem - whose proof I will never remember without having to drag calculus in there - that says that the variation of momentum is equal to the force applied times the time the application last.
As long as the engine isn't ejecting mass - at this point it's a whole new can of worm - we know the force, we know the variation in speed, time to find the mass. But first, let's convert the variation of speed in meters per second. The ship gains 250 kmh, 
;
Nuclear fusion reactions convert protons into helium; thus, becoming the source of all energy radiated by the sun.
Answer: Option D
<u>Explanation:</u>
Nuclear fusion reaction is one among the two nuclear reactions in which the atoms nucleus interact with each other to produce the products. In nuclear fusion, two smaller atoms react together to form a new atom with bigger size.
So large amount of energy is required to start the nuclear fusion reaction. The fusion reactions mostly occurs in stars. The illumination in Stars even the Sun is due to nuclear fusion reaction occurring with the atoms present in them.
Mostly the energy radiated by Sun is due to the protons-protons chain reaction. In this chain reaction, the protons get converted into helium due to nuclear fusion reaction, thus becoming the source of all energy radiated by the Sun.
