Thre stones A, B and C are simultaneously projected from same point with same speed. A is thrown upwards, B is thrown horizontally and C is thrown downwards from a boulding. When the distance between stone A and C becomes 10 m, then distance between A and B will be-

Options

A. 10 m
B. 5 m
C. `5^(sqrt(2))m`
D. `10^(sqrt(2))m`

Answer

C

Explanation

Let the stones be projected at t = 0 sec with a speed u from point O. Then an observer, at rest at t = 0 and having constant acceleration equal to acceleration due to gravity, shall observe the three stones moves with constant velocity as shown.

In the given time each ball shall travel a distance 5 metre as seen by this observer. Hence the required distance between A and B will be `= sqrt(5^(2)+5^(2))=5sqrt(2)` metre.