Question

You press a book against a vertical wall. Express the force required to hold the book in place, Fapplied
, in terms of Wbook
and μs
.(1 point)
Responses

Fapplied=Wbook/μs
upper F subscript applied baseline equals upper W subscript book baseline divided by mu subscript s baseline

Fapplied=μsWbook
upper F subscript applied baseline equal mu subscript s baseline upper W subscript book baseline

Fapplied=Wbook/μk
upper F subscript applied baseline equals upper W subscript book baseline divided by mu subscript k baseline

Fapplied=μkWbook

Answer 1

To hold a book against a vertical wall, you need to apply a force that overcomes the gravitational force (weight) acting on the book and the friction between the book and the wall.

The weight of the book is given by \( W_{\text{book}} \).

The frictional force \( F_{\text{friction}} \) that helps keep the book in place is given by:

\[
F_{\text{friction}} = \mu_s F_{\text{normal}}
\]

where \( F_{\text{normal}} \) is the applied force \( F_{\text{applied}} \) that you exert on the book to press it against the wall, and \( \mu_s \) is the coefficient of static friction.

For the book to remain stationary against the wall, the frictional force must balance the weight of the book:

\[
F_{\text{friction}} = W_{\text{book}}
\]

Substituting the expression for frictional force:

\[
\mu_s F_{\text{applied}} = W_{\text{book}}
\]

Now solving for the applied force \( F_{\text{applied}} \):

\[
F_{\text{applied}} = \frac{W_{\text{book}}}{\mu_s}
\]

Thus, the correct expression for the force required to hold the book in place is:

\[
F_{\text{applied}} = \frac{W_{\text{book}}}{\mu_s}
\]

So the correct response is:

**Fapplied = Wbook / μs**