Kinematics and Dynamics Lab Experiments

Laboratory experiments in mechanics test the predictions of kinematics and dynamics against real data.

Classic experiments

Measuring $g$ from a pendulum

$$g = \frac{4\pi^2 L}{T^2}$$

Plot $T^{2}$ vs $L$: the slope is $4\pi^{2}/g$.

Practical tips

• Use photogates or video analysis for accurate timing.
• Measure multiple periods and divide: $T = t_{10}/10$ reduces timing error by $10\times$.
• Friction is the main source of systematic error — minimise it or account for it.

import math
L = 1.00    # metres
T = 2.006   # seconds (measured)
g = 4 * math.pi**2 * L / T**2
print(f"g = {g:.2f} m/s^{2}")

Key insight: The best lab experiments are designed so that one variable is plotted against another to give a straight line. The slope or intercept gives the physical quantity of interest.

Common pitfall: Change one variable at a time. Varying mass and force together "to save runs" produces data from which neither effect can be untangled — a lost afternoon disguised as efficiency.