A girl is carrying a school bag of 3 kg mass on her back and moves 200 m on a lavelled road. If the value of g be `10 m//s^(2)`, the work done by the girl against the gravitational force will be :

Options

A. 6000 J
B. 0.6 J
C. 0 J
D. 6 J

Explanation

To find the work done by the girl against the gravitational force while carrying a school bag, we can follow these steps:

### Step 1: Identify the forces acting on the bag
The force acting on the bag due to gravity can be calculated using the formula:
\[ F = m \cdot g \]
Where:
- \( m \) = mass of the bag = 3 kg
- \( g \) = acceleration due to gravity = 10 m/s²

### Step 2: Calculate the gravitational force
Substituting the values:
\[ F = 3 \, \text{kg} \cdot 10 \, \text{m/s}^2 = 30 \, \text{N} \]
This is the force acting downward on the bag.

### Step 3: Determine the displacement
The girl moves a distance of 200 m on a levelled road. The displacement \( s \) is:
\[ s = 200 \, \text{m} \]

### Step 4: Determine the angle between force and displacement
Since the girl is moving horizontally while the gravitational force acts vertically downwards, the angle \( \theta \) between the gravitational force and the displacement is:
\[ \theta = 90^\circ \]

### Step 5: Use the work done formula
The work done \( W \) against the gravitational force can be calculated using the formula:
\[ W = F \cdot s \cdot \cos(\theta) \]
Substituting the values we have:
\[ W = 30 \, \text{N} \cdot 200 \, \text{m} \cdot \cos(90^\circ) \]

### Step 6: Calculate \( \cos(90^\circ) \)
We know that:
\[ \cos(90^\circ) = 0 \]

### Step 7: Calculate the work done
Thus, substituting \( \cos(90^\circ) \) into the equation:
\[ W = 30 \, \text{N} \cdot 200 \, \text{m} \cdot 0 = 0 \, \text{J} \]

### Conclusion
The work done by the girl against the gravitational force is:
\[ \text{Work Done} = 0 \, \text{Joules} \]