Atruck travels due east for a distance of 1.9 km, turns around and goes due west for 8.7 km, and finally turns around again and travels 3.0 km due east. (a) what is the total distance that the truck travels? km (b) what are the magnitude and direction of the truck's displacement?

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

In science and physics what is the standard unit of measure for speed?

Aparticle's position is given by x = 3.00 - 9.00t + 3t2, in which x is in meters and t is in seconds. (a) what is its velocity at t = 1 s? (b) is it moving in the positive or negative direction of x just then? (c) what is its speed just then? (d) is the speed increasing or decreasing just then? (try answering the next two questions without further calculation.) (e) is there ever an instant when the velocity is zero? if so, give the time t; if not, answer "0". (f) is there a time after t = 3 s when the particle is moving in the negative direction of x? if so, give the time t; if not, answer "0".