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A pole vaulter leaves the ground to travel 4.0 m up and over the bar, and then another 4.0 m back to the ground. It takes 1.81 s for the whole trip. Calculate the velocity with which she left the ground?
- billrussell42Lv 72 months ago
so it takes 0.905 s up and the same down.
v = gt = 9.8 x 0.905 = 8.87 m/s
h = ½gt² = ½9.8•0.905² = 3.77 m
which is NOT 4 m, so something is off....
if we use the 4 m number
v = √(2gh) = √(2•9.8•4) = 8.85 m/s
take you pick.
falling object starting from rest
h is height in meters, t is time falling in seconds,
g is acceleration of gravity, usually 9.8 m/s²
v is velocity in m/s
h = ½gt²
t = √(2h/g)
v = √(2gh)
h = v²/2g
v = gt