Suppose two particles `1 and 2` are projected in vertical plane simultaneously.
Their angles of projection are `30^@ and theta`, respectively, with the horizontal. Let they collide after a time`t` in air. Then
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Two particles are projected simultaneously in the same vertical plane, with speed u_(1) and u_(2) at angle of projection theta_(1) and theta_(2) respectively with the horizontal. The path followed by one, as seen by other (as long as both are in flight), is

Two particles are projected simultaneously in the same vertical plane, from the with speed u_(1) and u_(2) at angle of projection theta_(1) and theta_(2) respectively with the horizontal. The path followed by one, as seen by other (as long as both are in flight), is

Two particles are projected with same speed but at angles of projection (45^(@)-theta) and (45^(@)+theta) . Then their horizontal ranges are in the ratio of

Two particles A and B are projected simultaneously in the direction shown in the figure with velocities V_(A)=20m//s and V_(B)=10m//s respectively. If they collide in air after 1/2 sec. then

Two particles are projected simultaneously with same speed V_0 in same vertical plane at angle 30^@ and 60^@ With the horizontal .The time at which their velocities becomes parallel is

Two particles are projected simultaneously with same speed V_0 in same vertical plane at angle 30^@ and 60^@ With the horizontal .The time at which their velocities becomes parallel is