Question

A woman walks at 2.1 m/s due East. After 199 seconds, she changes her direction by 20° to the South at 2.9 m/s for 187 seconds. What is the distance between where she started and where she ended?

Answer 1

Find her displacement due East:

$$E=v_Et_E.$$

Her displacement due South:

$$S=v_St_S.$$

The distance between where she started and where she ended:

$$d=\sqrt{E^2+S^2}=\sqrt{(v_Et_E)^2+(v_St_S)^2},\\ d=\sqrt{(2.1\cdot199)^2+(2.9\cdot187)^2}=685\text{ m}.$$