Experiment to verify conservation of momentum by colliding trolleys on a smooth surface, measuring distances, and comparing initial and final momentum.
Apparatus
This experiment requires two carts with frictionless wheels and springs, two wooden bumpers, a meter scale, and a self-indicating balance. Additionally, a spirit level is used to ensure the table remains perfectly horizontal before beginning the setup.
Observations and Calculations
Zero correction of spring balance = ……… N
Mass of Cart 1 = ……… kg
Mass of Cart 2 = ……… kg
Initial velocity of loaded carts = zero
| No.. of Obs. | Mass of | Distance covered | Momentum | Final Momentum M1 x1 – m2 x2 | |||
| Cart I M1 Kg | Cart 2 M2 kg | Cart 1 X1 m | Cart 2 X2 m | Cart 1 m1 X1 | Cart 2 m2 X2 | ||
Procedure
Begin the experiment by checking the table’s level with a spirit level. After ensuring it is balanced, fix the wooden bumpers at both ends so that the moving carts stop safely. Next, use the self-indicating balance to determine the masses of both carts accurately.
Then, position the carts side by side at the midpoint between the bumpers. When the spring in the loaded exploder is released by removing the pin (P), it pushes the carts in opposite directions. Consequently, both carts start moving and eventually hit the bumpers at the edges of the table.
After several trials, observe when both carts take equal time to reach the bumpers. At this stage, the motion becomes balanced, and you can record the final positions. Therefore, this confirms that momentum is conserved during the process.
Inference
The momentum before the collision equals the momentum after the collision.
Hence, the law of conservation of momentum is verified successfully.
Precautions
-
Keep the table’s surface smooth and level to avoid frictional resistance.
-
Oil the wheels regularly so that the carts move freely.
-
Always measure the distance from the inner edge of the bumper to the rear side of each cart.
-
Additionally, repeat the experiment several times to minimize error.
Viva Voce
Q.1. What is the principle of momentum?
Ans. Momentum in an isolated system remains constant unless an external force acts on it.
Q.2. Is it possible to exert a force and still transfer no energy?
Ans. Yes. When a force acts at a right angle to the direction of motion, no energy transfer occurs.
Q.3. What role does momentum play in a collision?
Ans. It ensures that total momentum remains conserved in both elastic and inelastic collisions.
Q.4. What happens to a car’s momentum when it stops?
Ans. The car transfers most of its momentum to the earth through the road and a small portion to the surrounding air molecules.