Question

Whenever a body is thrown vertically upwards with a certain velocity, the upwards motion is opposed by gravitational pull of earth and resisatnce of air. The velocity of the body goes on decreasing at a constant rate `(= - g)`.As soon as upward velocity of body becomes zero, it cannot rise any more. The height it has attained is the maximum height. The body then begins to fall downwards with an acceleration `= g`.
Read the above passege and answer the following questions :
(i) A body is thrown upwards with a velocity of `19.6 m//s`. What is the maximum height attained?
(ii) With what velocity will the body hit the ground?
(iii) What are the implications of this study in day to day life ?

Answer 1

(i) Here, `u= 19.6 m//s, upsilon = 0, a = - g = - 9.8 m//s^(2), s = h = ?`
from `upsilon^(2) - u^(2) = 2 as`
`0 - (19.6)^(2) = 2 (-9.8)h`
`h = 19.6 m`
(ii) If we ignore resistance due to air and other stray losses of energy, them the body will hit the ground with the same velocity `= 19.6 m//s`, with which it was thrown.
(iii) In day to day life, our progress and rise in carrer is opposed by several factors influding jealousy of your friends and foes. It is the initail kick (i.e., powerful stars) and continuous motivation that lead us to our desired goel.