PHYSICS · Single correct · CBSE · Physics · Work and Energy · Work and Energy
Problem
A 1.0kg book rests on a shelf 2.0m above the floor. Student A chooses the floor as the zero of gravitational potential energy, whereas Student B chooses the shelf as the zero. Which statement about the gravitational potential energy U of the book is most accurate?
(a) Only Student A’s reference choice is valid; Student B’s choice leads to incorrect physics.
(b) Students A and B obtain different numerical values for U, but any change in U calculated for a subsequent motion of the book is the same for both students.
(c) Students A and B obtain the same numerical value for U because the value of g is the same for both references.
(d) Student B’s choice makes U negative while Student A’s makes it positive, and the change in U is different for the two students.