Relative Velocity Simulation
Example 3.9: Trains and Monkey
This simulation demonstrates relative velocity concepts with two trains moving in opposite directions and a monkey moving on one train. Observe how velocities change in different reference frames.
Positive direction: North (from South to North)
Train A: +54 km/h North | Train B: -90 km/h South | Monkey: -18 km/h South relative to Train A
North (+)
South (-)
Given Velocities
Train A (North): +54 km/h
Train B (South): -90 km/h
Monkey (relative to A): -18 km/h
Solutions
(a) Velocity of B wrt A: -144 km/h
(b) Velocity of ground wrt B: 90 km/h
(c) Velocity of monkey wrt ground: 36 km/h
Reference Frames
• Ground frame (stationary)
• Train A frame (moving North)
• Train B frame (moving South)
Calculations
\( \vec{v}_{BA} = \vec{v}_B - \vec{v}_A = -90 - 54 = -144 \, \text{km/h} \)
\( \vec{v}_{GB} = -\vec{v}_B = 90 \, \text{km/h} \)
\( \vec{v}_{MG} = \vec{v}_{MA} + \vec{v}_{AG} = -18 + 54 = 36 \, \text{km/h} \)
