- #1
Gumbosplat
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Homework Statement
Ok, so I'm doing this science fair project on tennis ball bounce hieght, and I have to find the force that it hits the ground with. I'm trying to do this mathematically, because I can't record the time accurately in the actual experiment.
The mass of the ball is 0.0567kg, the acceleration is just gravity, 9.8m/s/s, and the height of the drop varies; 0.2m, 0.4m, 0.6m, and 1m.
I just need to know how to calculate time, but I'm not sure what the equation is. I tried t=√2d/a, but that gives me very weird results.
Homework Equations
t=√2d/a (?)
v=d/t
F=m(Δv/Δt)
The Attempt at a Solution
so for the 0.2m height, I did these calculations.
d=0.2m
a=9.8m/s/s
m=0.0567kg
t=√2d/a
t=√0.4m/9.8m/s/s
t=√0.40s/s
t=0.2s
v=d/t
v=0.2m/0.2s
v=1m/s
F=m(Δv/Δt)
F=0.0567kg(1m/s /0.2s)
F=0.0567kg(5.0m/s/s)
F=0.284N
and for the 0.4m height, I did
d=0.4m
a=9.8m/s/s
m=0.0567kg
t=√2d/a
t=√0.8m/9.8m/s/s
t=√0.08s/s
t=0.894s
v=d/t
v=0.4m/0.894s
v=0.447m/s
but that doesn't make sense! how can the velocity be less from a greater height? I feel like I'm doing the time equation wrong, and I've looked everywhere online and can't find a reliable time from distance and acceleration equation. This is driving me crazy, please help! Also, am I calculating impact force correctly?