A lamp of negligible height is placed on the ground m away from a wall
MATHEMATICS · Single correct · AP · Calculus AB · Contextual Applications of Differentiation · Contextual Applications of Differentiation
Problem
A lamp of negligible height is placed on the ground l1 m away from a wall. A man l2 m tall is walking at a speed of 10l1 m/s from the lamp to the nearest point on the wall. When he is midway between the lamp and the wall, the rate of change in the length of this shadow on the wall is
(a) −25l2 m/s
(b) −52l2 m/s
(c) −2l2 m/s
(d) −5l2 m/s