Question

A stone is projected vertically up from the top of a tower at a velocity 9.8 M per second it reaches the foot of the building in 4 seconds what is the height of the tower and velocity of the stone when it reaches the ground

Answer 1

V=0
u=9.8m/s
total time=4sec
g=9.8m/s square
t= u/g
= 9.8/9.8
=1sec to go up
therefore time to come down =3sec
height = u square/2g
=(9.8) square/2×9.8
=4.9m
height =1/2gt square
1/2 (9.8)*(3)square
=44.1m
height of the building =44.1-4.9
=39.2m
v=gt
= 9.8*3
=29.4m/s