Question: Mass of Box A = $8.0$ kg
Mass of Box B = $12$ kg
Applied force = $60$ N (to the right)
Surface is frictionless
Find:
Acceleration of the system
Tension in the rope when box b is getting a horizontal force of $60$N to the right
1. **State the problem:**
We have two boxes, A and B, connected by a rope on a frictionless surface. Box B is pulled to the right with a force of $60$ N. We need to find the acceleration of the system and the tension in the rope.
2. **Identify known values:**
- Mass of Box A, $m_A = 8.0$ kg
- Mass of Box B, $m_B = 12$ kg
- Applied force on Box B, $F = 60$ N
- Surface is frictionless, so no friction force.
3. **Find acceleration of the system:**
Since the boxes are connected, they accelerate together with the same acceleration $a$.
Total mass, $m_{total} = m_A + m_B = 8.0 + 12 = 20$ kg
Using Newton's second law:
$$F = m_{total} \times a$$
Solve for acceleration:
$$a = \frac{F}{m_{total}} = \frac{60}{20} = 3\ \text{m/s}^2$$
4. **Find tension in the rope:**
The tension $T$ acts on Box A to accelerate it.
Using Newton's second law on Box A:
$$T = m_A \times a = 8.0 \times 3 = 24\ \text{N}$$
5. **Summary:**
- Acceleration of the system is $3\ \text{m/s}^2$
- Tension in the rope is $24$ N
This means the rope pulls Box A with $24$ N to accelerate it at $3\ \text{m/s}^2$, while Box B is pulled by the external force of $60$ N.