An object is projected from a height of 80 m above the ground with a velocity of 40ms-1 at an angle of 30° to the horizontal. The time of flight [ g ≈ 10m/s\(^2\)
8 s
4 s
16 s
10 s
Explanation
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Discussions (14)
How about the time for it to fall from 80m after the parabollic flight? You just calculated the time of flight through th parabolic path.
So i think something like this should be added.
S=1/2* g*t square
t=4s
4+4=8s (A) answer
I think we could also use one of the formulas of motion
S=½(u+v)t
::h=½(u+v)t
Where h=80,u=0,v=40,t=?
80=½(0+40)t
80=½(40)t
80×2=40t
160=40t
t=160/40=4
::t=4secs
The time of flight is the time taken to move from the point of projection to the point of landing, in this case the point of landing is 80m below the point of projection.
so the normal time of flight formula wont be sufficient after all the object wont halfway down.
so the time of flight is the to travel from point of projection to the level of projection plus time to travel below the level of projection which is 80m below
The time taken to fall 80m with gravity wasn't included. If included, the answer should be 8s.
