[Physics] If work is a scalar measurement, why do we sometimes represent it as the product of force (a vector) and distance (scalar)

displacementdistancenewtonian-mechanicsvectorswork

Consider an object being pushed 3/4 of the distance around a circular track. The work done on the object would be the distance of 3/4 the track’s circumference times the force applied to the object (given that it was pushed at a constant force). Since we are multiplying a vector by a scalar, why is work a scalar measurement? Or would the work done on the object actually just be force times displacement? Thanks.

Best Answer

Work is the dot product of a vector force and a vector displacement, hence a scalar.

Knowing just the scalar distance isn’t enough to calculate work. That distance might be in the same direction as the force, but it might be perpendicular or even opposed. All of those would give different values for the work done.