Question

(1) 20 m
tum
A stone is dropped from the top of a tower. If it travels 34.3 m in the last second before it reaches the ground,
find the height of the tower. (g=9.8 m/s²)
(1) 39.2 m
(2) 58.8 m
(3) 78.4 m
(4) 98 m
A freel fallinn nhiert falls through a height h in the noch second, What is the fall of height in the next second?​

Answer 1

Answer:

Option (3) - 78.4 m

Explanation:

In the last second,

t=1 s

a=g=9.8 m/s²

h= 34.3 m

h= ut+1/2 at²

34.3= u*1+1/2*9.8*1²

34.3= u+1/2*9.8*1

34.3= u+4.9

u= 34.3 - 4.9

u= 29.4 m/s

v = u+at

v= 29.4+9.8*1

v= 29.4+9.8

v= 39.2 m/s

Thus, v= 39.2 m/s ; u = 0 m/s (when dropped from the top of the tower) ; a=9.8 m/s²

time taken to reach the ground, t= v-u/a

= 39.2-0/9.8

= 39.2/9.8

= 4 s

h= ut+1/2 gt²

h= 0+1/2*9.8*4²

h= 1/2*9.8*16

h= 8*9.8

h= 78.4 m

HOPE THIS HELPS!!!