Block On Incline
1. **State the problem:** A 130 kg block slides down an inclined plane with a coefficient of kinetic friction $\mu_k = 0.25$. We need to find (a) the net force on the block and (b) the acceleration of the block down the incline.
2. **Identify forces and formulas:** Let the incline angle be $\theta$. Since it is not given, we assume it is known or we express answers in terms of $\theta$.
The forces acting on the block are:
- Gravitational force component down the incline: $F_g = mg\sin\theta$
- Frictional force opposing motion: $F_f = \mu_k N = \mu_k mg\cos\theta$
Net force down the incline is:
$$F_{net} = mg\sin\theta - \mu_k mg\cos\theta$$
Acceleration is given by Newton's second law:
$$a = \frac{F_{net}}{m} = g(\sin\theta - \mu_k \cos\theta)$$
3. **Calculate net force:**
$$F_{net} = 130 \times 9.8 \times (\sin\theta - 0.25 \cos\theta) = 1274 (\sin\theta - 0.25 \cos\theta)$$
4. **Calculate acceleration:**
$$a = 9.8 (\sin\theta - 0.25 \cos\theta)$$
**Summary:**
- Net force on the block is $F_{net} = 1274 (\sin\theta - 0.25 \cos\theta)$ Newtons.
- Acceleration of the block is $a = 9.8 (\sin\theta - 0.25 \cos\theta)$ m/s$^2$.
If the incline angle $\theta$ is provided, substitute its value to get numerical answers.