Can someone help me solve this question :explain how you would measure the external diameter of a measuring cylinder

you can use a vernier calliper

Explanation:

or you can calculate the circumference of the cylinder then, Then divide that amount by π

OR

measure the diameter divide it by two(2)

use a rope and tie it around the cylinder and make such you notice the two meeting points of your rope, which you use as a measuring tool, then you took the marked rope and you stretch it on a tape measure and there you get your reading from the tape measure.

Explanation:

v=ir = 3x15 =45 v

this could be newton#'s law of cooling. the cooling curve is exponential