Answer:
Explanation:
b) Gravity reduces the initial upward velocity to zero in a time of
t = v/g = 40/10 = 4 s
a) h = v₀t + ½gt² = 40(4) + ½(-10)4² = 80 m
or
v² = u² + 2as
h = (0² - 40²) / 2(-10) = 80 m
Answer:

Explanation:
Radius of the pollen is given as

Volume of the pollen is given as



mass of the pollen is given as


so weight of the pollen is given as



Now electric force on the pollen is given



now ratio of electric force and weight is given as


Answer:
b. 
Explanation:
As we know that the electric field due to infinite line charge is given as

here we can find potential difference between two points using the relation

now we have

now we have

now plug in all values in it


now we know by energy conservation


Answer:
"C" I think....
Explanation:
I am really sorry if I am wrong, but if right, I hope this helps!