Question

A 3.50 kg book slides along a rough horizontal surface. Initially, the book is traveling at 2.25 m/s. At some later point, the book is traveling at 1.87 m/s. What is the work done on the book?

a) -7.1 J
b) -11.4 J
c) 7.1 J
d) 11.4 J

Answer 1

The work done on the book is calculated using the work-energy principle, resulting in a loss of energy due to friction, with the correct answer being -7.1 J.

Step-by-step explanation:

The student is asking for the work done on a book as it slides across a rough horizontal surface and slows down from an initial speed to a lower speed. To solve this, we can use the work-energy principle which states that the work done on an object is equal to the change in its kinetic energy.

First, we calculate the initial kinetic energy (KEi) and the final kinetic energy (KEf) of the book using the formula KE = (1/2)mv2, where m is the mass of the book and v is its velocity.

KEi = (1/2)(3.50 kg)(2.25 m/s)2
KEf = (1/2)(3.50 kg)(1.87 m/s)2

Then, we find the work done (W) by calculating the difference between KEi and KEf:

W = KEf - KEi

The work done on the book is negative, indicating that energy has been lost due to friction. The correct answer for the work done on the book is -7.1 J, which corresponds to option (a).