Answer:
Explanation:
Photon is also a particle . Hence when two particles like electron and positron annihilate to get completely changed to photons , a minimum of two photons of equal and opposite momentum and energy are produced flying in opposite direction to conserve momentum and energy . Each photon will have same energy equal to 511 keV . It is so to conserve momentum and energy. Initially total momentum was zero so finally too total momentum should be zero.
The so-called "terminal velocity" is the fastest that something can fall
through a fluid. Even though there's a constant force pulling it through,
the friction or resistance of plowing through the surrounding substance
gets bigger as the speed grows, so there's some speed where the resistance
is equal to the pulling force, and then the falling object can't go any faster.
A few examples:
-- the terminal velocity of a sky-diver falling through air,
-- the terminal velocity of a pecan falling through honey,
-- the terminal velocity of a stone falling through water.
It's not possible to say that "the terminal velocity is ----- miles per hour".
If any of these things changes, then the terminal velocity changes too:
-- weight of the falling object
-- shape of the object
-- surface texture (smoothness) of the object
-- density of the surrounding fluid
-- viscosity of the surrounding fluid .
The answer is D using the work formula
W= F•d but if it was against gravity, it would be 0 if gravity is exerting the same amount, I would pick D using the formula, but I'm not so sure sorry
That is true Step by step:
Sample:
As soon as the lightning is seen, sound travels in the air for several kilometers until it eventually reaches the observer.
