A speedy tortoise can run at .08 m/s, and a hare can run 18 times as fast. In a race, they start at the same time, but the hare stops to rest for 2.7 min, so the tortoise wins by 20 cm. How long does the race take? Answer in units of s.
2007-01-25 13:04:39 · 2 answers · asked by Anonymous in Science & Mathematics ➔ Physics
distance is the distance from start to finish
time is equal
tortoise
d=8 cm/s *t
for the hare
d-20=18*8*(t-2.7*60)sec
d=144*(t-162)+20
or
8*t=144*(t-162)+20
t=171.38 s
j
2007-01-25 13:13:19 · answer #1 · answered by odu83 7 · 0⤊ 0⤋
Answer: 171.38 seconds. And the race length was 13.71 meters.
The hare speed is 18 times 0.08 = 1.44 m/s.
The rest was 2.7 minutes = 162 seconds.
The formula is:
(L -0.2) / 1.44 + 162 = L / 0.08
From which we can find the L = 13.71059 meters.
Then the tortoise's time is L / 0.08 = 171.3824 seconds.
2007-01-25 21:23:59 · answer #2 · answered by morningfoxnorth 6 · 0⤊ 0⤋