Arocket travels vertically at a speed of 800 km/hr. the rocket is tracked through a telescope by an observer located 13 km from the launching pad. find the rate at which the angle between the telescope and the ground is increasing 3 min after lift-off. (round your answer to two decimal places.)

The rocket's altitude at time is

so that after , it will have traveled

The angle of elevation at time is such that

At the moment when , this angle is

Differentiating both sides of the equation above gives

and substituting the angle found above, and , we get

when insulating materials rub against each other, they may become electrically charged . electrons , which are negatively charged, may be 'rubbed off' one material and on to the other. the material that gains electrons becomes negatively charged. the material that loses electrons is left with a positive charge.