A stone is thrown vertically upwards with an intinal velocity of 20 m/sec. find the maximum height it reaches and the time by it reachthe height (g=10 m/sec).

Maximum height is20m and time taken will be 2second

Explanation:

vi=20m/s

vf=0m/s

g=10m/s^2

Using third equation for objects falling freely

2gh = (vf) ^2 - (vi) ^2

Putting values

2 (10m/s^2) h = (0m/s) ^2 - (20m/s) ^2

20h=400m

h=20m

Now we have to find the time

Using first equation of motion for objects falling down freely

vf=vi+at

substituting the equation

(vf-vi) / g=t

(0-20) / 10=t

t=2second