Answer: 4.37 J
Explanation:
The work done by a constant force is given by:
[tex]W=Fd cos \theta[/tex]
where
F is the magnitude of the force
d is the distance through which the object has been moved
[tex]\theta[/tex] is the angle between the direction of the force and of the motion of the object.
In this problem:
- the magnitude of the force of friction is F = 1.9 N
- the distance is d = 2.3 m
- the angle is [tex]\theta=180^{\circ}[/tex], because the direction of the friction is opposite to the direction of motion of the book
Therefore, the work done is
[tex]W=(1.9 N)(2.3 m)(cos 180^{\circ})=-4.37 J[/tex]
