Two masses, [tex]$m_1 = 5 \, \text{kg}$[/tex] and [tex]$m_2 = 48 \, \text{kg}$[/tex], tied to a string are hanging over a light, frictionless pulley.

The acceleration of the system when left free to move is:
1. [tex][tex]$4.8 \, \text{m/s}^2$[/tex][/tex]
2. [tex]$2.98 \, \text{m/s}^2$[/tex]
3. [tex]$5 \, \text{m/s}$[/tex]
4. [tex][tex]$0.2 \, \text{m/s}^2$[/tex][/tex]

Select the correct option.



Answer :

Let's work through the problem step-by-step to find the acceleration of the system involving two masses [tex]\( m_1 = 5 \, \text{kg} \)[/tex] and [tex]\( m_2 = 48 \, \text{kg} \)[/tex] hanging over a light, frictionless pulley. We are asked to find the acceleration of the system.

### Step 1: Analyze the forces acting on each mass
- For the mass [tex]\( m_1 \)[/tex]:
- The only force acting on [tex]\( m_1 \)[/tex] is its weight [tex]\((m_1 \cdot g)\)[/tex], which acts downward.

- For the mass [tex]\( m_2 \)[/tex]:
- The only force acting on [tex]\( m_2 \)[/tex] is its weight [tex]\((m_2 \cdot g)\)[/tex], which acts downward.

### Step 2: Set up the equations of motion
Since the pulley is frictionless, both masses will accelerate with the same magnitude of acceleration [tex]\( a \)[/tex].

- For [tex]\( m_1 \)[/tex]:
[tex]\[ T - m_1 \cdot g = m_1 \cdot a \][/tex]

- For [tex]\( m_2 \)[/tex]:
[tex]\[ m_2 \cdot g - T = m_2 \cdot a \][/tex]

Here, [tex]\( T \)[/tex] represents the tension in the string.

### Step 3: Combine the equations
To eliminate [tex]\( T \)[/tex], let's add the two equations together:

[tex]\[ (m_2 \cdot g - T) + (T - m_1 \cdot g) = m_2 \cdot a + m_1 \cdot a \][/tex]

This simplifies to:
[tex]\[ m_2 \cdot g - m_1 \cdot g = (m_1 + m_2) \cdot a \][/tex]

### Step 4: Solve for acceleration [tex]\( a \)[/tex]
Factor out [tex]\( g \)[/tex] on the left side of the equation:

[tex]\[ (m_2 - m_1) \cdot g = (m_1 + m_2) \cdot a \][/tex]

Now, solve for [tex]\( a \)[/tex]:

[tex]\[ a = \frac{(m_2 - m_1) \cdot g}{m_1 + m_2} \][/tex]

### Step 5: Substitute the given values [tex]\( m_1 = 5 \, \text{kg} \)[/tex], [tex]\( m_2 = 48 \, \text{kg} \)[/tex], and [tex]\( g = 9.8 \, \text{m/s}^2 \)[/tex]
[tex]\[ a = \frac{(48 \, \text{kg} - 5 \, \text{kg}) \cdot 9.8 \, \text{m/s}^2}{5 \, \text{kg} + 48 \, \text{kg}} \][/tex]

This simplifies to:

[tex]\[ a = \frac{43 \cdot 9.8}{53} \][/tex]

### Conclusion
The result is an acceleration [tex]\( a \approx 7.950943396226416 \, \text{m/s}^2 \)[/tex].

Thus, the correct answer is:
[tex]\[ a \approx 7.951 \, \text{m/s}^2 \][/tex]