Question

Two tall buildings are `30 m` apart. The speed with which a ball must be thrown horizontally from a window `150 m` above the ground in one building so that it enters a window `27.5 m` from the ground in the other building is.
A. `2 m s^-1`
B. `6 m s^-1`
C. `4 m s^-1`
D. `8 m s^-1`

Answer 1

Correct Answer - B
(b) `h = 150 - 27.5 = 122.5 m`
Time taken, `T = sqrt((2 h)/(g)) = sqrt((2 xx 122.5)/(9.8)) = 5 s`
Now `s = uT` or `30 = 5u` or `u = 6 ms^-1`.