The x-axis runs along the principal axis of a concave mirror, with the origin at the vertex and the real focus at (5.75 cm,0). The mirror is facing the positive x-axis. A toy car of height 21 cm starts at the real focus and moves at constant velocity v = +2.94i cm/s (away from the mirror). Find the rate at which the height of the image size is changing, in cm/s, at the instant the car reaches (86.4 cm,0). The sign will indicate if it the value of the height of the image is increasing or decreasing. HINT: Watch out for signs! Think about the sign of image height!

The x-axis runs along the principal axis of a concave mirror, with the origin at the vertex and the real focus at (5.75 cm,0). The mirror is facing the positive x-axis. A toy car of height 21 cm starts at the real focus and moves at constant velocity v = +2.94i cm/s (away from the mirror). Find the rate at which the height of the image size is changing, in cm/s, at the instant the car reaches (86.4 cm,0). The sign will indicate if it the value of the height of the image is increasing or decreasing. HINT: Watch out for signs! Think about the sign of image height!