I cant figure out this question on average speed.
I know average speed is d2-d1/t2-t1.
I have d2 being 1.5km and d1 being .8km
My times are .017hr and .012hr.
I keep getting 140 for my average speed which makes no sense cuz I had 85km/hr and 67km/hr to begin with.
The orginal question was an antelope can run 1.5km with an average speed of 85km/hr and then it ran .8km with an average speed of 67 km/hr.
Find the average speed during its whole run - I figured the time to be 1.74 min.
Anyways can you help me figure out why I'm getting 140km/hr for my average speed??
2006-09-17 04:32:41 · 7 answers · asked by MellyMel 4 in Science & Mathematics ➔ Physics
your equation is wrong. It should be
average speed = (D1 + D2)/(T1 + T2)
If you do the calculation again you will come up with 79.3 km/hour. That makes sense because it is between the two speeds.
2006-09-17 04:42:05 · answer #1 · answered by xox_bass_player_xox 6 · 3⤊ 1⤋
average speed : -
say there is a car moving. it moves with a velocity of 20m/s for 60s and then with a velocity of 30m/s for another 60s.
now,
total distance traveled by the car is (20*60)+(30*60).
i.e; 300m.
now total time taken = (60+60) = 120.
therefore, average velocity = 300/120 = 2.5m/s.
now that means if the same car instead of moving with a velocity
of 20m/s for 60s and then with a velocity of 30m/s for another 60s,
it moves with a velocity of 2.5m/s for 120s, it will cover the same
distance.
i hope this will help you clear your doubt.
2006-09-17 11:54:39 · answer #2 · answered by go4sambhav 1 · 1⤊ 0⤋
first part : d =1.5, s = 85km/hr, t1 = d/s = 1.5/85 hr = 0.01765 hr
second part : d = 0.8, s = 67, t2 = 0.8/67 hr = 0.01194
total dist = 1.5 + 0.8 = 2.3 km
total time = t1 + t2 = 0.02959 hr
av speed = 2.3/0.02959 = 77.7 km/hr
2006-09-17 11:50:13 · answer #3 · answered by wimafrobor 2 · 1⤊ 0⤋
time taken by the antelope for 1st run=
t= d/s = 1.5 / 85 =0.017 hrs
time taken by the antelope for 2nd run=
t= d/s = 0.8 / 67 =0.012 hrs
total time taken = 0.029 hrs
total distance = 1.5+0.8=2.3kms
avg speed = 2.3 / 0.029 = 79.3 km/hr.
2006-09-17 11:47:46 · answer #4 · answered by jazideol 3 · 1⤊ 0⤋
You have your D values mixed up. Remember that the first D in the equation should be the second D in the problem.
2006-09-17 11:36:34 · answer #5 · answered by Anonymous · 0⤊ 0⤋
Way too much science for me. Ur smart. Im only a freshman...
2006-09-17 11:40:34 · answer #6 · answered by SaTa D 2 · 0⤊ 0⤋
xox_bass_... is correct. You divide total distance by total time.
2006-09-17 14:03:18 · answer #7 · answered by STEVEN F 7 · 0⤊ 0⤋