Question

A stone is thrown in vertically upward direction with a velocity of 5m/s. If the acceleration during it's motion is 10m/s square in downward direction, what will be the height attained by the stone and time.

Answer 1

v^2=2as
25=2×10×s
s=1.25 m

Answer 2

AnswEr:

$\bf{Given}\begin{cases}\sf{Initial\:velocity,u=5m/s}\\\sf{Final\:velocity,v=0}\\ \sf{Acceleration,a=10ms-^2}\\\sf{Time,t=?}\\\sf{height,h=?} \end{cases}$

Using 1st equation of motion

$\qquad \sf \: v = u + at \\ \\ \qquad \sf \rightarrow \frac{v - u}{a} = t \\ \\ \qquad \rightarrow \sf \: \frac{0 - 5}{ - 10} = t \\ \\ \rightarrow \sf t = 0.5 \: s$

Using 3rd equation of motion :

$\qquad \sf \: {v}^{2} - {u}^{2} = 2as \\ \\ \qquad \rightarrow \sf \: \frac{ {v}^{2} - {u}^{2} }{2as} = s \\ \\ \qquad \sf \rightarrow \: \frac{0 - 25}{2 \times1 0} = 5 \\ \\ \sf \rightarrow \: 1.25 \: m$