Question

A body is projected vertically upward. If it's velocity after 2 s is 25 m s $^{–1}$, find the velocity of projection.​

Answer 1

~$\small \blue {\sf{Answer }}$✨❤

The value of the velocity in its downward motion will be same. But it will have opposite direction. So in the upward journey if the velocity = u, in the downward journey in the same point the velocity will be (-u).

v 2 =u 2 +2as

s =0 ⟹ v= ±u

where + is for projection and - is for return.

$\huge \orange {\mathfrak{Thank You }}$

Answer 2

Answer:

Given:-

v = 25 m s $^{–1}$

g = 10 m s $^{–2}$, (since value of g wasn't given I have taken the value of g as 10 m s $^{–2}$)

t = 2 s

To find:-

Velocity of projection.

Solution:-

We know that,

v = u – gt

Now keeping the value of v, g and t, we get

$\Longrightarrow$ 25 = u – 10(2)

$\Longrightarrow$ u = 25 + 20

= 45 m s$^{–1}$

Thus, velocity of projection is 45 m s $^{–1}$