Question

3. Answer the
a) A stone is thrown vertically upwards such that it reaches the maximum height of
20 m. Calculate the initial speed of the stone. Consider the value of acceleration due
to gravity as 10 m/s2
h) Derive the expression for kinetic energy.​

Answer 1

Explanation:

Let u be the initial velocity and h be the maximum height attained by the stone.

v12=u2−2gh,

(10)2=u2−2×10×2h

100=u2−10h ....(i)

Again at height h,

v22=u2−2gh

(0)2=u2−2×10×h

u2=20h  ... (ii)

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

100=10h

h=10m