Average <u>speed</u> = (distance covered) / (time to cover the distance) =
(5m) / (15 sec) =
(5/15) (m/s) = <em>1/3 m/s</em> .
Average <u>velocity</u> =
(displacement) / (time spent traveling) in the direction of the displacement
Average velocity = (5m) / (15 sec) left =
(5/15) / (m/sec) left =
<em>1/3 m/s left</em>.
A number without a direction is a speed, not a velocity.
Just ignore the horizontal component
if you have a vertical displacement of 15m, 0ms^1 initial velocity, end velocity is ignored, we know the acceleration due to gravity as 9.81ms^2 so we can work out the time using SUVAT
S=15
U=0
V=?
A=9.81
T=?
S=UT + 0.5 AT^2
UT=0
therefore,
S=0.5AT^2
rearrange to:
T=SQR (2S/A)
T = 1.75 seconds