A ball is thrown at different angles with the same speed u and from the same point. It has the same range in both cases. If `y_(1)` and `y_(2)` be the heights attained in the two cases, then `y_(1) +y_(2)` equals to

Options

A. `(u^(2))/(g)`
B. `(2u^(2))/(g)`
C. `(u^(2))/(2g)`
D. `(u^(2))/(4g)`

Answer

C

Explanation

Range R=same
then angles of projecion are `theta & (90-theta)`
`y_(1)=(u^(2)sin^(2)theta)/(2g)` and
`y_(2)=(u^(2)sin^(2)(90^(@)-theta))/(2g)=(u^(2)cos ^(2)theta)/(2g)`
`y_(1)+y_(2)=(u^(2))/(2g)(sin^(2) theta+cos^(2)theta)=(u^(2))/(2g)`