From the top of a clif,100m above sea level ,a stone is thrown vertically upward with a velocity of 3om/s.After how many secounds and what velocity?

Tifepraise

3 years ago

Firstly we need to find the Maximum height of projection from the clifftop.

Using, V^2=U^2 2gh.

V=0

U=30

g=10

h=?

Substituting,

0^2=30^2 2*10*h

Make h the subject of the formula.

h=900/20.

h=45m. Now we find the time taken to reach maximum height. V=U gt. t=30/10. t=3seconds.

Adding h to H, we have 45 100=145m

Now we can find the Final Velocity and time of the downward projection.

Using, V^2=U^2 2gH.

But U=0

So, V^2=2gH

2*10*145=2900.

V=[2900

Find SquareRoot

V=54m/s...............(ans1)

To find time, we use:

V=U gt

54=0 10t

t=54/10

t=5.4seconds. Add this time to the time taken to reach maximum height-3seconds and you have 8.4seconds as the total time.