Both speed and velocity measure how fast something is moving. however, since speed is not a it does not require a(n) . a) quantity, unit b) magnitude, unit c) vector, direction d) scalar, direction

Both speed and velocity measure how fast something is moving. Hence, since speed is not a vector it does not require direction.

Speed only depends on the distance covered by the object and how much time it took to cover that distance. It does not care about the direction, it just depend on the length of the entire path covered. Whereas, velocity depends on magnitude as well as the direction of the object's motion for example: When an airplane is traveling, It is better to deal the motion with velocity and when we are moving in a car inside the city, we should deal the motion with speed.  

this is poiselle's equation from fluid mechanic in physics. mech eng

the displacement produced by the body.  

the amount of force subjected to the body.  

the angle between the direction of force and displacement