multiple choice question\nwhich describes the speed of an object and not the velocity of an object?\no 400…

Brief Explanations:

Speed is a scalar quantity, having only magnitude. Velocity is a vector quantity, having both magnitude and direction. 400 km/h west and 800 km/h west have direction so they are velocities. 800 km west is a displacement, not speed or velocity. 800 km/h has only magnitude and represents speed.

Answer:

800 km/h