In the lens maker's equation, what value will f approach if the index of refraction of the surroundings equals that of the material itself?
lens equation: 1/f = 1/do + 1/di
can you explain how the equation answers the question? do not answer if you do not understand the equation thoroughly.

The transfer of heat through the movement of a gas or liquid a. convection b. conduction c. radiation

Arunner is training for an upcoming marathon by running around a 100-m-diameter circular track at constant speed. let a coordinate system have its origin at the center of the circle with the x-axis pointing east and the y-axis north. the runner starts at (x, y) = (50 m, 0 m) and runs 2.5 times around the track in a clockwise direction.

Arocket starts from rest and moves upward from the surface of the earth. for the first 10.0 s of its motion, the vertical acceleration of the rocket is given by ay = 12.80 m/s32t, where the +y-direction is upward. (a) what is the height of the rocket above the surface of the earth at t = 10.0 s? b) what is the speed of the rocket when it is 325 m above the surface of the earth?