Question

a stone is dropped from the top of a tower travels 35m in last second of journey. the height of the tower is.

Answer 1

Dear student,
s= ut + (1/2)ft²
in the last second, t= 1 second, s= 35m, and f=g= 9.8 m/s²
so,
35 = u + 0.5×9.8
=》 u= 35 -4.9 = 30.1 m/s.
now initial velocity, u₁= 0, final velocity, u= 30.1 m/a,
Now, u² - u₁² = 2fs
=》 s = [(30.1)² - 0]/(2×9.8)
=》 s = 46.225 m
initial velocity u₁=0, final velocity
so height of the tower
H= 35+46.225 = 81.225 m

Regards.