2002

1. (a) A stone is thrown vertically upwards under gravity with a speed of u m/s from a point 30 metres above the horizontal ground.
The stone hits the ground 5 seconds later.

(i) Find the value of u..

(ii) Find the speed with which the stone hits the ground.

ANSWER

(i) Take the starting point as the origin.
Then, landing on the ground 30 metres below would represent a displacement of -30.
 
No "v"
           
 

 

(ii)