Height of the body from the ground can be calculated by using the formula `h=-ut+(1//2)^(g t^2)` in
(a) A body projected vertically with velocity 'u' from the top of tower, reaches the ground in 't' sec.
( b) A body dropped from a balloon moving up with uniform velocity, reaches the ground in 't' sec
(c) A body dropped from a helicopter moving up with uniform velocity, reaches the ground in 't' sec
(d) A body projected vertically from the ground reaches the ground in 't' sec.

Options

A. a, b and c are correct
B. a, b, c and d are correct
C. a is only correct
D. b and d are correct

Answer

A