Force Position
1. **Problem Statement:**
We have a block of mass $m=5.35$ kg subjected to a position-dependent force along the x-axis given by
$$\vec{F}(x) = \left(21.85\frac{N}{m}x - 9.08\frac{N}{m^2}x^2\right)\hat{i}$$
with initial position $\vec{r}_i = 0.97\,m\hat{i}$ and initial velocity $\vec{v}_i = 7.91\frac{m}{s}\hat{i}$. The coefficient of kinetic friction is $\mu_k = 0.433$.
2. **Goal:**
Analyze the force function and understand the motion of the block under this force and friction.
3. **Force Function Analysis:**
The force depends on position $x$ as
$$F(x) = 21.85x - 9.08x^2$$
where $F$ is in Newtons and $x$ in meters.
4. **Important Concepts:**
- The force is nonlinear due to the $x^2$ term.
- The friction force opposing motion is $F_f = \mu_k mg$.
- Newton's second law: $F_{net} = ma = m\frac{d^2x}{dt^2}$.
5. **Net Force on the Block:**
$$F_{net}(x) = F(x) - F_f = 21.85x - 9.08x^2 - \mu_k mg$$
Substitute values:
$$F_f = 0.433 \times 5.35 \times 9.8 = 22.68\,N$$
So,
$$F_{net}(x) = 21.85x - 9.08x^2 - 22.68$$
6. **Equation of Motion:**
Using $F_{net} = m a$:
$$5.35 \frac{d^2x}{dt^2} = 21.85x - 9.08x^2 - 22.68$$
or
$$\frac{d^2x}{dt^2} = \frac{21.85}{5.35}x - \frac{9.08}{5.35}x^2 - \frac{22.68}{5.35}$$
7. **Interpretation:**
This nonlinear second-order differential equation governs the block's motion considering the position-dependent force and friction.
8. **Graph Shape:**
The force $F(x)$ is a quadratic function opening downward (since coefficient of $x^2$ is negative), with zeros at $x=0$ and $x=\frac{21.85}{9.08} \approx 2.41$ m.
9. **Summary:**
The block experiences a nonlinear restoring force and constant friction opposing motion. The initial conditions $x=0.97$ m and $v=7.91$ m/s set the starting state for solving the motion equation.
**Final note:** To fully solve for $x(t)$, numerical methods or further analysis are needed due to nonlinearity.