1. One object is fired at an angle of ten degrees above the horizontal. A second object is fired at an
angle of ten degrees below the horizontal, and a third is fired in an exactly horizontal direction.
All three are fired at the same time, but with different (and nonzero) speeds. Neglect air
resistance and assume that the objects are fired over a perfectly level plain. Which of the objects
strikes the ground first?
A.
(a) The one fired at an angle of ten degrees above the horizontal.
B.
(b) The one fired at an angle of ten degrees below the horizontal.
C.
(c) The one fired exactly horizontally.
D.
(d) They will all strike the ground at the same time.
E.
(e) You cannot tell from the information given.
F.
(f) None of the answers above is correct.
Solution
b) The one fired at an angle of ten degrees below the horizontal.
There is component of velocity verticaly downwards due to which by formula s =ut+1/2 gt2

2. time is minimum for one fired at an angle of ten degrees below the horizontal.