Question

A body dropped from the top of a tower covers a distance $7h$ in the last second of its journey where h is the distance covered in the first second. How much time does it take to reach the ground?

• A. $3s$
• B. $4s$
• C. $5s$
• D. $6s$

Answer 1

The correct option is B $4s$

apply given formula

$h=0+\frac{1}{2}\ast g\ast (2\ast 1-1)⟹h=\frac{g}{2}$

distance covered in last second $=7h\frac{7g}{2}=\frac{g}{2}(2t-1)t=4sec.$