A body of mass 120 g placed at the 10cm mark on a uniform meter rule makes the rule settle horizontally on a full Cron placed at 35 cm mark , calculate the mass of the rule and also show the diagram ?

To calculate the mass of the meter rule, we can use the principle of moments.

Let the mass of the meter rule be M grams. The total clockwise moment about the fulcrum due to the body and the meter rule is equal to the total anticlockwise moment about the fulcrum due to the body and the meter rule.

Clockwise moment = 120g x 10cm = 1200 g.cm
Anticlockwise moment = M x 35cm

Therefore, 1200 = M x 35
M = 1200 / 35
M = 34.29 g

So, the mass of the meter rule is 34.29 grams.

Diagram:
```
0 cm ------------------------------------ 35 cm
|---------------------|------------------|
| 120 g | M |
|---------------------|------------------|
```