To find the position of a point half a second earlier in a frame moving at \(10 \, \text{cm/s}\), subtract the displacement due to the frame's motion from the current position. Here, the displacement in half a second is:
\[\Delta x = 10 \, \text{cm/s} \times 0.5 \, \text{s} = 5 \, \text{cm}\]
Thus, the position half a second earlier, moving backward along the x-axis, is:
\[x_{\text{earlier}} = 11 \, \text{cm} + 5 \, \text{cm} = 16 \, \text{cm}\]
The y-coordinate remains unchanged as the movement is only along the x-axis.