A child's balloon rises into the air at a rate of 2.5 ft/sec. The child runs over to his mom (5.75 feet from where he lost it) and watches the balloon ascend into the sky. How fast is the angle of observation, Θ, changing (in radians per second) at the moment when the balloon is 18 feet above the ground?
I found that the angle of observation is changing at 0.14 rad/sec. Could somebody please confirm this for me?