Hey!
NOTE-:
u= initial velocity
v= final velocity
g= acceleration due to gravity
t= time
u= 0
v= 49 m/s
t=?
g= 9.8 m/s^2
Using first equation of motion -
v-u=at
49-0= 9.8×t
49 = 9.8t
49/9.8= t
t= 5 second
Hope it helps...!!!
Power is the energy transferred or "WORK DONE" in one second
Atmospheric refraction is the deviation of light or other electromagnetic wave from a straight line as it passes through the atmosphere due to the variation in air density as a function of height. ... Refraction not only affects visible light rays, but all electromagnetic radiation, although in varying degrees.
So in short, the answer is D.
(My answer got deleted because it didnt explain which is dumb)
A.) <span>If no unbalanced force acts upon the house of cards, then it will remain standing forever.
[ Other Statements doesn't make any sense in Physics, they can be true in some situation & can't be false, option A is the only answer ]
Hope this helps!</span>