Introductory physics leans heavily on algebra and trigonometry, which means the TI-84 skills you already use in math class transfer directly to kinematics, vectors, and unit conversions in physics. This guide shows how to set up the calculator for common physics problem types.
Introduction
Physics problems often involve several related formulas applied in sequence — finding velocity, then using it to find displacement, for instance — which makes the TI-84's variable storage especially useful for keeping intermediate results organized and reusable.
This guide covers entering and rearranging the kinematics equations, working with vectors in component form, storing physical constants, handling unit conversions, and graphing position or velocity over time.
Kinematics Equations on the Home Screen
The four standard kinematics equations relate displacement, initial and final velocity, acceleration, and time. Rather than memorizing a calculator-specific method, store each known value to a variable — V for initial velocity, A for acceleration, T for time — then type the relevant formula directly, such as V*T+.5*A*T² for displacement.
When a problem asks you to solve for a variable that isn't isolated in the formula, either rearrange the equation algebraically on paper first, or use the calculator's solver feature (MATH → 0:Solver) to solve for a variable without manually rearranging, entering the equation as written and providing a guess value.
Working with Vectors
For vector addition given magnitude and angle, break each vector into x and y components using cos and sin: a vector of magnitude M at angle θ has components (M·cos(θ), M·sin(θ)). Store each component, then add the x-components together and the y-components together to get the resultant vector's components.
To convert the resultant back to magnitude and angle form, use √(x² + y²) for magnitude and tan⁻¹(y/x) for the angle, adjusting the angle by 180° if x is negative, since tan⁻¹ alone cannot distinguish between the first and third quadrants (or second and fourth). The TI-84's ANGLE menu also includes R►Pr( and R►Pθ( functions that convert rectangular coordinates to polar form directly, handling this quadrant adjustment automatically.
Storing Constants and Formulas
For problems reusing the same constant repeatedly, such as g = 9.8 m/s² for gravity, store it once with 9.8 STO→ G and reference G in every formula for the rest of the problem set, rather than retyping 9.8 each time and risking a typo partway through.
For a sequence of related sub-questions (common in multi-part physics problems), store each intermediate answer to a new variable letter as you go, so later parts can reference earlier results directly, such as using the velocity found in part (a) as an input to part (b) without re-copying the decimal value by hand.
Unit Conversions
The TI-84 does not have built-in unit conversion like some scientific calculators, so conversions must be done through multiplication by a conversion factor — for example, multiplying a speed in km/h by (1000/3600) converts it to m/s. Storing common conversion factors as variables at the start of a problem set saves time across multiple similar conversions.
Always double-check the direction of a conversion (multiplying versus dividing) by sanity-checking the result's magnitude — converting a small number of miles into a much larger number of feet should produce a bigger number, and reversing that expectation is a strong sign the conversion factor was applied backwards.
Graphing Motion
Position, velocity, and acceleration graphs can be entered directly as functions of time in the Y= screen (using X to represent time), letting you visualize motion the same way you'd graph any other function. Graphing position and its derivative side by side reinforces the relationship between the two, similar to the techniques covered in this site's calculus guide.
For motion described piecewise (like an object that accelerates, then moves at constant velocity, then decelerates), graph each phase as a separate function restricted to its time interval, or use a piecewise-defined Y1 with the calculator's inequality-based restriction syntax to combine all phases into a single graph.
Further Reading & Sources