Section 18
Guide to approaching a problem
When the problem statement does not indicate the formula, use the problem signal to choose the appropriate formula block. Then open that section of the catalog and review the validity conditions.
Signal
Components, magnitude, dot or cross product, unit vector
Method
Vectors
Signal
Position, velocity, or acceleration in a straight line; 1D free fall
Method
1D Kinematics
Signal
Projectile, range, maximum height, time of flight
Method
2D and 3D Motion
Signal
Forces, free-body diagram, inclined plane, friction, tension
Method
Newton's laws
Signal
Curve, , centripetal acceleration, rotation period
Method
Circular motion
Signal
Work, kinetic/potential energy, power, conservation of energy
Method
Work, energy and power
Signal
Collision, impulse, “before/after”, conservation of momentum
Method
Momentum, impulse, and collisions
Signal
Disk, wheel, torque, moment of inertia,
Method
Rotation
Signal
Static equilibrium, center of mass, spring (Hooke) without oscillating
Method
Equilibrium and elasticity
Signal
Gravity between masses, orbits, satellites, escape velocity
Method
Gravitation
Signal
Pressure, buoyancy, flow rate, Bernoulli
Method
Fluid mechanics
Signal
Spring or pendulum, period, frequency, harmonic motion
Method
Oscillations
Signal
Traveling wave, wavelength, interference, intensity
Method
Waves
Signal
Sound, beats, Doppler effect, level in decibels
Method
Sound
Signal
Heat, temperature, ideal gas, first law, heat engines
Method
Thermodynamics
Signal
Charge, Coulomb, field/potential, Ohm, R circuits, capacitors
Method
Basic electricity
Signal
You need , , , , or another numerical constant
Method
Physical constants
Practical review order#
Practical review order
- Identify the system and draw a sketch (forces, trajectory, or circuit).
- Classify the problem type using the table above.
- Choose the requested quantity (position, force, energy, current, etc.).
- Write down known data and SI units.
- Apply the main formula and check its conditions.
- If there are several stages (e.g. collision + energy), chain related formulas.
- Check signs, dimensions, and whether the result is reasonable.