A car wants to travel 2 miles, with an average speed of 60 miles per hour. For the 1st mile the car averages 30 mile per hour, how fast must the car on average travel for the 2nd miles to meet this average of 60 miles per hour? Please show all work and how you came up with it!
2006-12-15 12:51:55 · 7 answers · asked by Dan C 1 in Science & Mathematics ➔ Physics
Too many Dan C's...
In physics class we came up with the problem, and new it could NOT be possible, but we couldn't really find a way to prove it with math...
2006-12-15 13:11:24 · update #1
30 miles per hour is the same as saying it takes 2 minutes to go 1 mile (30 miles/ hr x 1 hr/ 60 minutes = 1/2 miles per minute)
60 miles / hour x 1 hour/ 60 minutes is one mile per minute
2 miles would take two minutes at 60 mph. However, we already used two minutes to go one mile at 30 mph. The car would instantaneously move the last mile- faster even than the speed of light so this my friend is impossible
2006-12-15 13:02:29 · answer #1 · answered by MrWiz 4 · 1⤊ 1⤋
USING LOGIC
A car traveling an average of 60 miles an hour will travel 2miles in two minutes because a car averaging that speed will average 1 mile per minute for 60 minutes. A car traveling at half that speed or 30 miles per hour will need two minutes per mile. Since it traveled one mile at 30 MPH it already took up two minutes so it cannot average 60 for those two miles without going at infinite speed. In other words it is impossible to average 60 MPH for two miles after already going one mile at 30 MPH.
USING MATH
1mile/30 MilesPerHour + 1mile/ X MilesPerHour = 2miles/ 60 MilesPerHour
simplifying
2min + 1mile/ X milesperhour= 2min
simplify further
1mile/X miles per hour = 0
Attempting to solve for X would require inverting the equation resulting in division by zero which means the equation is not valid and cannot be satisfied. In other words "IMPOSSIBLE"
2006-12-15 13:20:15 · answer #2 · answered by ny_lollippop 2 · 0⤊ 0⤋
90 miles an hour 30 + 90 = 120/ 2 = 60 mph
2006-12-15 13:04:54 · answer #3 · answered by Josh T 3 · 0⤊ 1⤋
Average speed is (total distance / time of travel)
V1 (average during the 1st mile) = 1 / t1 = 30 mile/ hour.
V2 (average during the 2nd mile) = 1 / t2
V3 (average during the 2 miles) = 2 / (t1 + t2) = 60 mile/hour.
t1 = 1/30 hour
t1 + t2 = 2/60 = 1/30 hour
t2 = zero. and V2 = infinity.
2006-12-15 14:01:40 · answer #4 · answered by Pearlsawme 7 · 0⤊ 0⤋
simple......disregard those answers that mention the speed of light as they are way wrong.........
the first mile you traveled at 30 mph under your desired speed therefore the second mile would have to travel 30 mph over the desired speed which would be 90mph
2006-12-15 14:00:28 · answer #5 · answered by James O only logical answer D 4 · 0⤊ 0⤋
velocity is velocity with course. velocity is distance being travelled through the years at a given 2nd and self sufficient of course. generic velocity is distance travelled through the years taken. Acceleration is fee of substitute of velocity, i.e. the substitute in course, or the substitute of linear velocity through the years.
2016-12-11 09:58:39 · answer #6 · answered by vannostrand 4 · 0⤊ 0⤋
Dan C I saw you on the news today...!!
☆ http://www.osoq.com/funstuff/extra/extra03.asp?strName=Dan_C
2006-12-15 13:06:17 · answer #7 · answered by bfd f 1 · 0⤊ 0⤋