posted by Anonymous .
compare your average speed in the following cases.
a. you walk 73.2 m at a speed of 1.2 m/s and then run 73.2 m at a speed of 3.1 m/s along a straight track.
b. you walk 1 min. at a speed of 1.2 m/s and then run for 1 min. at 3.1 m/s along a straight track.
(a)since time=distance/speed, you have
total distance: 73.2+73.2=146.4m
total time: 73.2/1.2 + 73.2/3.1 = 84.6s
avg speed: 146.4m/84.6s = 1.73 m/s
do (b) the same way