Question

A stone is thrown vertically upwards with an initial velocity of 20m/sec. Find the maximum height ot reaches and the time taken by it to reach the height. (g=10m/s2)

plz short numerical ASAP​

Answer 1

The height reached is 20m, The time taken to reach 20m is 2 seconds

Step-by-step explanation:

Observing the equations of motion we can see that the following equation will be most helpful for this question.

`v^(2) = u^(2) + 2as`

We are given initial velocity, u

We know that the stone will stop at its maximum height, so final velocity, v

Acceleration, a

And we are looking for the displacement (height reached), s

Substitute the values we are given into the equation

`0^(2) = 20^(2) + 2(10)s`

Rearrange for s

`0^(2) -20^(2) =20s`

`-400=20s`

`(-400)/(20) =s`

s = -20 (The negative is just showing direction, it can be ignored for now)

The height reached is 20m

Use a different equation to find the time taken

`s = vt - (1)/(2) at^(2)`

Substitute in the values we have

`-20=(0)t - (1)/(2) (10)t^(2)`

Rearrange for t

`-20 =0 -5 t^(2)`

`(-20)/(-5) =t^(2)`

`4 = t^(2)`

t = 2s

The time taken to reach 20m is 2 seconds