help pls fast
What is the purpose of a reference point
O to provide a standard system of measurement
O to establish a point from which to measure future distance, or if movement has occurred
O to determine the speed of an object in miles per hour
O to provide a standard from which to evaluate variables in an experiment

Which of the following quantities are units of momentum? (there could be more than one correct choice.) a)n m b) kg s/m c) kg m/'s d)n-s 12 points] e) kg m2/s2

Copper has free electrons per cubic meter. a 71.0-cm length of 12-gauge copper wire that is 2.05 mm in diameter carries 4.85 a of current. (a) how much time does it take for an electron to travel the length of the wire? (b) repeat part (a) for 6-gauge copper wire (diameter 4.12 mm) of the same length that carries the same current. (c) generally speaking, how does changing the diameter of a wire that carries a given amount of current affect the drift velocity of the electrons in the wire?

Which situation will produce the greatest change of momentum