Asked by Kala
A sprinter can accelerate with constant acceleration for 2.10s before reaching top speed. He can run the 100-meter dash in 10 s.
What is his speed as he crosses the finish line?
What is his speed as he crosses the finish line?
Answers
Answered by
Steve
the runner runs at top speed for 7.9 seconds, so
1/2 a*2.1^2 + 2.1a*7.9 = 100
a=5.32
v = at = 5.32*2.1 = 11.172 m/s
check:
accelerating at 5.32m/s^2 for 2.1 s gives
s = 1/2 * 5.32 * 2.1^2 = 11.73
From then on with speed = 5.32*2.1 = 11.172, the distance covered is
11.172*7.9 = 88.27
total distance: 100.0 m
1/2 a*2.1^2 + 2.1a*7.9 = 100
a=5.32
v = at = 5.32*2.1 = 11.172 m/s
check:
accelerating at 5.32m/s^2 for 2.1 s gives
s = 1/2 * 5.32 * 2.1^2 = 11.73
From then on with speed = 5.32*2.1 = 11.172, the distance covered is
11.172*7.9 = 88.27
total distance: 100.0 m
Answered by
Anonymous
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