Question

A stone is thrown vertically upwards with a speed of 20m/s. If g = 10m/s², find

(1) Time is taken by the stone to reach the maximum height.

(2) Total distance covered by the stone to reach the maximum height.

Answer 1

We are given that: Initial velocity (u) = 20 m/s

When an object attain maximum height, then final velocity (ν) = 0

a = g = 10m/s², time (t) = ?

(1) From first equation of motion, we have v = u – gt

⇒ 0 = 20 - 10 x t 

⇒ 10t = 20 

⇒ t = 2 sec

(2)  From third equation of motion, we have
v² = u² – 2gh

⇒ (0)² = (20)² - 2 x 10 x h

⇒ 20h = 20 x 20

⇒ h = 20 m