If a ladder of length 30 ft that is leaning against a wall has O its upper end sliding down the wall at a rate of 1/2 ft /sec, 36 rad/sec what is the rate of change of the acute angle made by the O 1 ladder with the ground when the upper end is 18 ft above rad/sec 48 the ground? 1 75 rad/sec O 1 100 rad/sec