A student performed an experiment to investigate the principle of conservation of momentum - Leaving Cert Physics - Question 1 - 2020

The student used an electronic balance to measure the masses of the trolleys. By placing each trolley on the scale, the mass was directly read from the digital display.

The student used a meter stick to measure the distance. The distance from the starting point of trolley A to the collision point was recorded. Markers could also be placed at defined intervals to help in measurements.

The time was measured using a stopwatch. The student started the stopwatch when the trolley was released and stopped it when the trolleys collided.

The student calculated the velocity using the formula:

$v = \frac{d}{t}$

where $v$ is the velocity, $d$ is the distance, and $t$ is the time taken. By plotting the distance against time, the slope of the line represents the velocity.

The combined momentum can be calculated using the formula:

$\text{Momentum} = (m_A + m_B) \times v_f$

Where:

• $m_A = 0.38$ kg
• $m_B = 0.35$ kg
• $v_f = 0.78$ m s⁻¹

So,

$(0.38 + 0.35) \times 0.78 = 0.569 \text{ kg m s}^{-1}$

Yes, momentum was conserved in this collision. The total momentum before the collision, 0.57 kg m s⁻¹, is equal to the combined momentum after the collision at 0.569 kg m s⁻¹, with very minimal discrepancy likely due to experimental error.