Question

A truck moves at a steady speed on a horizontal road. What is the work done by the road on the truck?

Answer 1

Step 1 Given

1. Truck is moving at a constant speed ie.$a=0$.

Step 2 Formula used,

1. Work done is defined as the dot product of force and displacement i.e.$W=\overrightarrow{F}.\overrightarrow{s}=\overrightarrow{|F}|\times |\overrightarrow{s}|\times \cos \theta$.

Step 3 solution,

1. Force applied by the road on the vehicle is $N$.
2. Although the truck does have a displacement over time, the force of the road on the truck is perpendicular to the motion.
3. Since force and displacement are perpendicular, the value$\cos \theta$ will be zero.
4. Therefore the dot product, in that case, will be zero.

Hence, the work done by the road on the truck is zero.