Question

3. A stone is dropped from the edge of a roof of tower
4.9 m tall. Time taken by the stone to strike the
ground is :
(a) 1 s
(b) 0.5 s
(c) 2 s
(d) none of these​

Answer 1

Answer:

0.5 seconds is the answer

Explanation:

hope it help you

Answer 2

To Find:-

Time to reach ground.

Solution:-

• We known that stone started from rest so the initial velocity of stone is 0.
• Let the time taken be ' t '

➣ ${\bf{\color{yelow}{ \: s\: \: = ut \: + \frac{1}{2}a {t}^{2} }}}$

➣ ${\bf{\color{yelow}{ \: 4.9\: \: = 0(t) \: + \frac{1}{2}\: × \: 9.8 \: × \: {t}^{2} }}}$

➣ ${\bf{\color{yelow}{ \: 4.9 \: = \: 4.9 {t}^{2} }}}$

➣ ${\bf{\color{yelow}{t \: = \: \sqrt{1} }}}$

➣ $\boxed{\bf{\color{yelow}{ \: t \: = \: 1 \: }}}$