Question

a stone is thrown vertically upwards such that it reaches the maximum height of 20m. Calculate the initial speed of the stone. Consider the value of acceleration due to gravity as 10m/s2​

Answer 1

maximum height attained by the stone.

v

1

2

=u

2

−2gh,

(10)

2

=u

2

−2×10×

2

h

100=u

2

−10h ....(i)

Again at height h,

v

2

2

=u

2

−2gh

(0)

2

=u

2

−2×10×h

u

2

=20h ... (ii)

So, from Eqs. (i) and (ii) we have

100=10h

h=10m