Goal: Problem solving with kinematics
Source: CT151.2-4
Ann is running with a constant speed of 3 m/s on a straight track. Deb
is also running with constant speed but is initially 10 m behind Ann. If
Deb catches up to Ann after Deb has traveled 55 m, how fast is Deb
running?
- 3.2 m/s
- 3.55 m/s
- 3.75 m/s
- 4.15 m/s
- More than 4.2 m/s
- none of the above
- cannot be determined
Commentary:
Answer
(6) The correct speed is 3.67 m/s. Students indicating #2 or #3
are likely making an arithmetic error. Have students graph the position
vs. time graphs for each runner.