Question

A stone falls down from the top of a wall in 1 s to the ground (g = 10 m/s²)

(a) What is the speed of the stone just before it touches the ground?

(b) Calculate the average speed when the stone is falling down

(c) How much is the height of the wall?

Answer 1

(a) v = u + at

= 0 + 10 x 1

= 10 m/s

(b) Average speed = \(\frac{Total\,distance}{Total\,time}\)

Total distance = S = ut + 1/2 at²

= 0 x 1 + 1/2 x 10 x 1²

= 5 m

Average speed = \(\frac{5}{1}\) = 5 m/s

(c) Height of wall = S = ut + 1/2 at²

= 5 m