What is the definition of precision? a. it is a measure of how close an observation is to the actual measurement. b. it is a measure of the repeatability of several measurement of the same observation. c. it has no meaning in science. d. it is a measure of the accuracy of an observation. e. none of the above are true.

An electron moves with a constant horizontal velocity of 3.0 × 106 m/s and no initial vertical velocity as it enters a deflector inside a tv tube. the electron strikes the screen after traveling 26 cm horizontally and 19 cm vertically upward with no horizontal acceleration. what is the constant vertical acceleration provided by the deflector? (the effects of gravity can be ignored.)