A2L Item 161

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

  1. 3.2 m/s
  2. 3.55 m/s
  3. 3.75 m/s
  4. 4.15 m/s
  5. More than 4.2 m/s
  6. none of the above
  7. cannot be determined



(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.