Classical Mechanics
Newton's laws, energy, momentum — the physics robots obey.
Why it matters in robotics
Classical mechanics is the foundation under everything a robot does physically: every dynamics model, controller, and trajectory optimizer rests on Newton's laws, torques, and energy/momentum conservation. Interviewers use mechanics questions as a cheap, fast filter for whether you can reason about forces and motion before they trust you with manipulator dynamics or contact-rich control. Expect to draw free-body diagrams, write and for a link or wheel, reason about moment of inertia and how mass distribution changes it, and apply conservation of momentum/energy to collisions, jumps, or impacts. A frequent failure mode is mixing up mass vs. moment of inertia, sign errors in torque, or forgetting constraint/friction forces, so clean FBD discipline and unit sanity-checks score well. Strong candidates connect the basics directly to robotics: why the inertia tensor matters for a spinning rotor, how friction cones bound graspable forces, and how energy methods simplify deriving equations of motion.
Application focus
The same topic, tailored to the robot you're building. Your choice is remembered across the roadmap and every topic.
At a glance
From a physical system to equations of motion: the core workflow you reproduce in interviews.
What to study
- ✓Forces, torques, and free-body diagrams: resolve forces, sum moments, and apply / to multi-body systems with constraints.
- ✓Work, energy, and momentum: kinetic/potential energy, the work-energy theorem, and conservation of linear and angular momentum (including elastic vs. inelastic collisions).
- ✓Rotational dynamics and moment of inertia: parallel-axis theorem, the inertia tensor, rolling without slipping, and angular momentum of rigid bodies.
- ✓Friction, contact, and constraints: static vs. kinetic friction, the friction cone, normal/contact forces, and how holonomic constraints reduce degrees of freedom.
Study by time budget
Pick the path that fits the time you have before your interview.