Question

What is the gravitational potential energy of each of the 2kg books in the image?

Answer 1

Given data:

* The mass of the book is m = 2 kg.

* The height of book A is h_A = 1 m.

* The height of book B is h_B = 1.5 m.

* The height of book C is h_C = 2 m.

Solution:

(a). The gravitational potential energy of book A is,

`U_A=\text{mgh}_A`

where g is the acceleration due to gravity,

Substituting the known values,

`\begin{gathered} U_A=2*9.8*1 \\ U_A=19.6\text{ J} \end{gathered}`

Thus, the gravitational potential energy of book A is 19.6 J.

(b). The gravitational potential energy of book B is,

`\begin{gathered} U_B=\text{mgh}_B \\ U_B=2*9.8*1.5 \\ U_B=29.4\text{ J} \end{gathered}`

Thus, the gravitational potential energy of book B is 29.4 J.

(c). The gravitational potential energy of book C is,

`\begin{gathered} U_C=\text{mgh}_C \\ U_C=2*9.8*2 \\ U_C=39.2\text{ J} \end{gathered}`

Thus, the gravitational potential energy of book C is 39.2 J.