A stone is thrown vertically upwards with a speed of 20 m/s. How high will it go before it begins to fall ? (g=9.8m/s2)
Given :
Initial velocity u = +20 m/s
Find velocity v = 0 m/sec
Gravity acceleration g = 9.8 m/s2
Distance s = ?
From 3rd equation of motion
v2−u2 = 2as
02−(+20)2= 2 × 9.8 × s
- 400 = 2 × 9.8 × s
s = −400/2×9.8 = – 20.4 m
Negative sign shows direction of displacement and gravity acceleration are opposite direction.
the distance = 20.4 m