Two physics students are trying to determine the instantaneous speed of a bicycle 5.0 m from the start of a 1000 m sprint. They use a stopwatch to measure the time taken for the bicycle to cover the first 10 m. If the acceleration was constant, and the measured time was 4.0 seconds, what was the instantaneous speed of the bicycle at the 5.0 m mark? [please explain in detail]!
The answer but how? [below]
It's NOT 2.5 m/sec BUT the answer 3.5m/sec <---how, please explain in detail!
2006-12-16 14:58:45 · 4 answers · asked by year 12 student 2 in Science & Mathematics ➔ Physics
s = 1/2 a t^2 is the formula I would use.
s = 10m
t = 4
so a = 2s/t^2 = 2*10/16 = 20/16
Now the speed at the 5 meter mark can be computed using
vf^2 = v0^2 + 2as where s = 5 m, and v0 is initial speed = 0
so vf^2 = 2*20/16*5 = 200/16 = 12.5
so vf is the square root of 12.5, which is about 3.5 (certainly between 3 and 4)
2006-12-16 15:07:27 · answer #1 · answered by firefly 6 · 2⤊ 0⤋
First, a = 2s/t² = 2*10/4² = 1.25
Knowing the value of a, the speed at the 5 m mark is
V = â(2ax) = â(2*1.25*5) = 3.536 m/s
2006-12-16 15:43:44 · answer #2 · answered by Steve 7 · 0⤊ 0⤋
The acceleration is given by 2*10m/(4s)^2
The speed at 5m is then
sqrt(2*5m*2*10m/(4s)^2) = 5/sqrt(2) ~3.5355
2006-12-16 15:40:37 · answer #3 · answered by arbiter007 6 · 0⤊ 0⤋
firefly is right lol he beat me.
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2006-12-16 15:13:52 · answer #4 · answered by Anonymous · 0⤊ 0⤋