(a) How long will a stone take to fall to the ground from the top of a building 80 m high and (b) what will be the velocity of the stone on reaching the ground? (take g=10m s⁻² ).
a. (a) 14 s, (b) 30 m s⁻¹
b. (a) 10 s, (b) 40 m s⁻¹
c. (a) 4 s, (b) 40 m s⁻¹
d. (a) 4 s, (b) 30 m s⁻¹