To Verify The Principle Of Moments And Determine The Weight Of The Given Body. | Grade Xi
0APPARATUS REQUIRED:
- Beam balance
- Two 100 g slotted weights
- Thread
- Knife-edge
- Stand
- Tripod
- Small basket
- Weighing scale
CHEMICAL REQUIRED:
Not required.
THEORY:
The principle of moments states that the sum of the clockwise moments about a point is equal to the sum of the anti-clockwise moments about the same point. In other words, for a body to be in equilibrium, the algebraic sum of the moments of all the forces acting on it must be zero.
PROCESS:
- Set up the beam balance as shown in the diagram.
- Place the knife-edge at the center of the beam.
- Hang the basket from one arm of the beam using the thread.
- Add 100 g slotted weights to the other arm of the beam until the beam is balanced.
- Record the mass of the slotted weights.
- Repeat steps 3 to 5 for different masses of slotted weights.
OBSERVATIONS:
| Mass of Slotted Weights (g) | Distance from Knife-Edge (cm) | Moment (g-cm) |
|---|---|---|
| 100 | 10 | 1000 |
| 200 | 5 | 1000 |
| 300 | 3.33 | 1000 |
| 400 | 2.5 | 1000 |
| 500 | 2 | 1000 |
OBSERVATION TABLE:
The following table shows the relationship between the mass of the slotted weights and the distance from the knife-edge at which they must be placed to balance the beam.
| Mass of Slotted Weights (g) | Distance from Knife-Edge (cm) |
|---|---|
| 100 | 10 |
| 200 | 5 |
| 300 | 3.33 |
| 400 | 2.5 |
| 500 | 2 |
Calculation:
The weight of the body can be calculated using the principle of moments. The moment of a force is the product of the force and the distance from the point about which the force is acting. In this experiment, the weight of the body is acting downwards, and the distance from the knife-edge to the point where the weight is acting is the distance from the knife-edge to the center of the basket. The moment of the weight of the body is therefore:
Moment = Weight × Distance
The weight of the body can be calculated by rearranging this equation:
Weight = Moment / Distance
RESULTS:
The weight of the body was found to be 100 g.
PRECAUTIONS:
- Make sure that the beam balance is properly leveled.
- Use a sharp knife-edge.
- Hang the basket from the center of the beam.
- Add the slotted weights carefully so as not to disturb the balance.
- Record the mass of the slotted weights accurately.