Question

Virtual Work done is saved in the form of potential energy. It is best given by ___________

(a) δU = Fδrcosθ

(b) δU = Fδrsinθ

(c) δU = Fδrcotθ

(d) δU = Fδrδθ

This question was posed to me in class test.

This question is from Potential Energy topic in portion Principle of Virtual Work of Engineering Mechanics

Answer 1

Correct option is (a) δU = Fδrcosθ

The explanation: The work is defined as the dot product of the δ force and the δ distance. This means that the work is done does depends upon the angle of the force. That is the angle which is being made by the force vector to the surface of action of the force.