How to determine the magnetic induction vector caused by a current element at a point

An object moves from the position +34m to the position -15m in 15 seconds. what is it's total displacement? what is it's average velocity?

What is a neurotransmitter involved in mood reward, addiction, and motor behaviors?

The scalar triple product computes the magnitude m of the moment of a force vector f about a specified line. it is m = (r × f) · n, where r is the position vector from the line to the point of application of the force and n is a unit vector in the direction of the line. use matlab to compute the magnitude m for the case where f = [12, −5, 4] n, r = [−3, 5, 2] m, and n = [6, 5, −7].