Question

For an object, which is projected vertically upwards the time of ascent when measured from the point of projection, will be (a) less the time of descent (b) greater the time of descent (c) equal to the time of descent (d none

Answer 1

Explanation:

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Answer 2

Time of Ascent:

The time taken by body thrown up  to reach maximum height h is called as time of ascent.

Let t₁ be time of ascent.

at maximim height , its velocity is zero, V=0

hence , V=u-gt

0=u-gt₁

t1=u/g ------------- (1)

Time of descent:

after reaching the maximum height, the body begins to travel downwards and reaches the ground.

The time taken to by a freely falling body to touch the ground is called time of descent.

Initial velocity for downward journey is zero  , u= 0

let t₂ be time of descent.

s=ut+1/2 gt²

h=0+1/2gt₂²

t2=√2h/g

but, h=u²/2g

so, we get

t₂=√2u²/2g

  =u/g---------------(2)

from equation 1 and 2 we can say

t₁=t₂

the time of ascent is equal to time descent in the case of bodies moving under gravity.