Physic Help
posted by Megan Lee .
In heavy rushhour traffic in Atlanta, you drive in a straight line at 21 mph for 5 miles. Then you have to stop for 10 minutes and finally drive slowly by a car wreck that is 2 miles away at a steady 15 mph. After the wreck, the road is clear, and you can drive the last 12 miles of your commute at 70 mph. What was the average speed of your commute home in mph?
I tried taking the average of the time but it was not the right answer.
Thanks

Physic Help 
Elena
t1=s1/v1 = 5/21=0.238 h
t2=10 min =0.167 h
t3=s3/v3=2/15=1.333 h
t4=s4/v4= 12/70=0.171 h
Total time t=t1+t2+t3+t4 =
= 0.238+0.167+1.333+0.171 =1.909 h.
Total distance s=s1+s3+s4=
=5+2+12=19 miles
Average speed is
v ave =total distance/time taken=
=s/t= 19/1.909=9.953 mph.
Respond to this Question
Similar Questions

Science  Physics
How long would it take you to drive from Houston to Gatorville LA (235 miles0 if you drive the first 75 miles at 60 mph, the next 100 miles at 65 mph, and the last 60 miles at 70 mph? 
Math
Issa is driving to the airport to catch a flight to Miami, and her arrival depends on traffic. If the traffic is light, then she can drive 60 mph and arrive at the airport 1 hour early. If traffic is heavy, she can drive 35 mph and … 
math
Issa IS driving to the airport to catch a flight to Miami, and Her arrival depends on traffic. If the traffic is light, then she can drive 60 mph and arrive at the airport 1 hour early. If traffic is heavy, she can drive 35 mph and … 
math
on a drive through allegheny county,natalie drove due west for 9 miles,then turned left and proceeded to drive due south.after traveling 12 miles south,what was the straight 12 miles line distance between where natalie startd and where … 
Alg 1
Issa is driving to the airport to catch a flight to miami, and her arrival depoends on traffic. If the traffic is light, then she can drive 60 mph and arrive at the airport 1 hour early. If traffic is heavy, she can drive 35 mph and … 
Algebra
I don't have a close about this question !!!!!!!! It takes you 3 hours to drive to a concert 135 miles away. You drive 55 miles per hour on highways and 40 miles per hour on the rest of the roads. How many miles do you drive on highways? 
PHYSICS
In heavy rushhour traffic you drive in a straight line at 12 m/s for 1.5 minutes, then you have to stop for 3.5 minutes, and finally you drive at 15 m/s for another 2.5 minutesPlot a positionversustime graph for this motion. Your … 
physics
can you graph this for me? In heavy rushhour traffic you drive in a straight line at 12 m/s for 1.5 minutes, then you have to stop for 3.5 minutes, and finally you drive at 15 m/s for another 2.5 minutes. A Plot a positionversustime 
Math
Avi drove from his home to college 60 miles per hour. Returning over the same route, there was a lot of traffic, and he was only able to drive at 40 miles per hour. If the return trip took one hour longer, how many miles did he drive … 
Physics
A car travels along a straight stretch of road if receipts for 13.6 miles at 55 mph than 25.8 miles at 48 mph and finally 43.1 miles at 33 mph what is the cart average velocity during the entire trip answer in units of miles per hour