Question

Using two billiard balls, in 3-4 sentences, design an experiment to demonstrate the law of conservation of momentum, including example calculations and measurements or an explanation of how to determine them.(4 points)

Answer 1

Place two identical billiard balls on a low‑friction pool table with ball A (m1 = 0.17 kg) rolled toward stationary ball B (m2 = 0.17 kg); measure each mass on a scale and measure velocities by filming the collision or using photogates/stopwatch over a known distance. For example, if you measure v1 = 1.20 m/s and v2 = 0.00 m/s before the collision, initial momentum p_i = m1·v1 + m2·v2 = 0.17·1.20 + 0.17·0 = 0.204 kg·m/s. After an approximately elastic head‑on collision of equal masses you should observe v1' ≈ 0.00 m/s and v2' ≈ 1.20 m/s, giving p_f = 0.17·0 + 0.17·1.20 = 0.204 kg·m/s, demonstrating momentum conservation within experimental error. Repeat several trials and minimize rotational/fractional losses to reduce discrepancies and quantify uncertainty from timing and measurement error.