Question -
Answer -
Given a man 160cm tall walks away from a source of lightsituated at the top of a pole 6 m high, at the rate of 1.1m/sec
To find the rate at which the length of his shadow increaseswhen he is 1m away from the pole
Let AB be the lamp post and let MN be the man of height 160cm or1.6m.
Let AL = l meter and MS be the shadow of the man
Let length of the shadow MS = s (as shown in the below figure)
Hence the rate at which the length of his shadow increases by0.4 m/sec, and it is independent to the current distance of the man from thebase of the light.