High School

An 18.0 kg mass is pushed across a carpeted floor with a force of -235 N. There is a +163 N force due to friction. What is the acceleration of the mass?

[tex]a = \, ? \, \text{m/s}^2[/tex]

Answer :

We are given:

- Mass: [tex]$m = 18.0\,\text{kg}$[/tex]
- Applied force: [tex]$F_{\text{applied}} = -235\,\text{N}$[/tex] (the negative sign indicates its direction)
- Friction force: [tex]$F_{\text{friction}} = +163\,\text{N}$[/tex] (opposite to the direction of the applied force)

Step 1: Calculate the net force

Add the forces to find the net force acting on the object:
[tex]$$
F_{\text{net}} = F_{\text{applied}} + F_{\text{friction}} = (-235\,\text{N}) + (163\,\text{N}) = -72\,\text{N}.
$$[/tex]

Step 2: Determine the acceleration

Using Newton's second law, [tex]$F = m \cdot a$[/tex], we can solve for the acceleration [tex]$a$[/tex]:
[tex]$$
a = \frac{F_{\text{net}}}{m} = \frac{-72\,\text{N}}{18.0\,\text{kg}} = -4.0\,\text{m/s}^2.
$$[/tex]

Thus, the acceleration of the mass is:
[tex]$$
\boxed{-4.0\,\text{m/s}^2}.
$$[/tex]