Question

42. Draw a free body of a block being held against a wall with an applied force of 10 N. Label all the forces and determine the magnitude if possible.

Answer 1

ANSWER and EXPLANATION

We want to draw the free body diagram of the block being held against the wall.

There are four forces acting on the block:

1. Force from the push

2. Normal force

3. Gravitational force/Weight

4. Frictional force

The free-body diagram is shown below:

where m = mass of the block

Fr = Frictional force

N = Normal force

Fp = Force from the push

Fg = Gravitational force/Weight

Since the block is in equilibrium, the net force in both horizontal and vertical directions must be 0.

Therefore, we have:

`\begin{gathered} F_{\text{hor}}=N-F_p=0 \\ \text{F}_{\text{ver}}=F_r-F_g=0 \end{gathered}`

As we can see, the magnitude of the Normal force will be equal to the magnitude of the force from the push and the magnitude of the Frictional force will be equal to the magnitude of the Gravitational force.

`\begin{gathered} N=F_p \\ F_r=F_g \end{gathered}`

We cannot calculate some of the values because the mass of the block and the coefficient of static friction are not given, but we have that:

`\begin{gathered} F_p=10N \\ \Rightarrow N=F_p=10N \end{gathered}`