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Free Physics Tool

Kinematics Solver

Enter any 3 of the 5 kinematic variables and get the complete step-by-step solution. Supports 1D linear motion and 2D projectile motion — perfect for PHYS 1401, WebAssign physics lab, and AP Physics.

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Client-Side Only 5 Variables 4 Equations 1D & 2D Motion
Motion Type:
Try: Car braking Free fall Rocket launch Stopping distance Find time

Enter any 3 known values and leave unknowns blank. Use negative values for opposite direction.

v₀
Initial Velocity
m/s
Blank = unknown
v
Final Velocity
m/s
Blank = unknown
a
Acceleration
m/s²
Blank = unknown
t
Time
s
Blank = unknown
Δx
Displacement
m
Blank = unknown

Your step-by-step solution will appear here

Enter at least 3 known kinematic values and click “Solve Kinematics”.

Step-by-Step Solution

The four kinematic equations cover every combination of the five variables. The solver automatically selects the equation that avoids your unknown variable.

Equation 1 — Velocity-Time
v = v₀ + at
Missing: Δx
Equation 2 — Position-Time
Δx = v₀t + ½at²
Missing: v
Equation 3 — Velocity-Displacement
v² = v₀² + 2aΔx
Missing: t
Equation 4 — Average Velocity
Δx = ½(v₀ + v)t
Missing: a

Decision Matrix

Known VariablesUnknownUse Equation
v₀, a, tvv = v₀ + at
v₀, v, att = (v−v₀)/a
v₀, v, taa = (v−v₀)/t
v₀, a, tΔxΔx = v₀t + ½at²
v₀, a, Δxvv² = v₀² + 2aΔx
v₀, v, Δxaa = (v²−v₀²)/(2Δx)
v₀, v, tΔxΔx = ½(v₀+v)t

A summary of the five kinematic variables, their standard symbols, SI units, and sign conventions.

SymbolVariableUnitSign ConventionNotes
v₀Initial Velocitym/s+ = rightward/upwardVelocity at t = 0
vFinal Velocitym/s+ = rightward/upwardVelocity at end of interval
aAccelerationm/s²+ = speeding up in + dir.Must be constant (uniform)
tTimesAlways positiveDuration of motion interval
ΔxDisplacementm+ = rightward/upwardΔx = x_final − x_initial

Key Constraint: Kinematic equations assume constant (uniform) acceleration. For free fall use a = −9.8 m/s².

Quick Guide

How to Use the Step-by-Step Kinematics Solver

1

Select Motion Type

Choose 1D Linear for straight-line problems or 2D Projectile for objects launched at angles.

2

Enter 3 Known Values

Fill in exactly 3 of the 5 fields (v₀, v, a, t, Δx). Leave unknowns blank. Negative values indicate opposite direction.

3

Click Solve

The physics engine selects the equation that does not involve the missing variables and isolates the unknown algebraically.

4

Read & Copy Steps

Each step shows the exact math — matching the format required in WebAssign physics lab reports and PHYS 1401 homework.

Educational Guide

The Complete Student Guide to Kinematics: PHYS 1401, WebAssign Physics Lab, and the Four Kinematic Equations

Kinematics is the mathematical language of motion. Before a physicist can describe forces, fields, or energy, they must first master position, velocity, acceleration, and time — the four pillars that define every moving object in classical mechanics. Whether you are enrolled in PHYS 1401 at a Texas community college, working through a WebAssign physics lab on projectile motion, or grinding through an AP Physics C free-response section, a reliable kinematics solver is the single most powerful tool in your academic arsenal.

kinematics solver PHYS 1401 kinematics WebAssign physics lab step-by-step kinematic equations projectile motion calculator 1D 2D motion solver

Understanding the Five Kinematic Variables

The entire framework of classical kinematics rests on just five quantities: initial velocity (v₀), final velocity (v), acceleration (a), time (t), and displacement (Δx). The power of the kinematic equations lies in a simple rule: if you know any three of these five variables, you can algebraically solve for the remaining two. This is the exact logic embedded in our kinematics solver. You provide three known values; the engine scans the four kinematic equations, identifies which one is solvable with your given data, and isolates the unknown. The resulting output is a complete step-by-step derivation — not just a number.

The Four Kinematic Equations: When to Use Each

Students enrolled in PHYS 1401 or any introductory physics course are expected to recognize and apply four core kinematic equations under exam conditions:

  • Equation 1 — v = v₀ + at: Use when you know initial velocity, acceleration, and time, and want to find the final velocity. Displacement is not involved.
  • Equation 2 — Δx = v₀t + ½at²: Use when you know initial velocity, acceleration, and time, and want to find displacement. The most common equation in WebAssign physics lab free-fall problems.
  • Equation 3 — v² = v₀² + 2aΔx: Use when time is unknown or irrelevant. Crucial for collision and braking distance problems.
  • Equation 4 — Δx = ½(v₀ + v)t: Use when acceleration is unknown. Relates displacement to the average of initial and final velocities over a time interval.

Pro Tip for WebAssign Physics Lab: WebAssign frequently asks you to show your setup before submitting the numerical answer. Our kinematics solver generates exactly that — the symbolic equation, the substitution step, the isolation step, and the final value. Screenshot or copy the steps directly into your lab report.

Isolating Variables: The Algebraic Strategy Every Physics Student Needs

The most common mistake students make on PHYS 1401 exams is selecting the wrong kinematic equation. The correct strategy: start by identifying what you do not know, then find the equation that does not contain that missing variable. For example, if you are given v₀, v, and Δx but not t, you need Equation 3 because it is the only equation relating those three variables without requiring t. Rearranging: a = (v² − v₀²) / (2Δx). This is precisely the selection and rearrangement logic that our kinematics solver executes automatically.

1D vs. 2D Kinematics: Decomposing Projectile Motion

Two-dimensional projectile motion is governed by the independence of horizontal and vertical motion:

  • Horizontal (x) component: Acceleration is zero (no air resistance). Horizontal velocity is constant: Δx = v₀ₓ ⋅ t.
  • Vertical (y) component: Acceleration equals gravity, aₑ = −9.8 m/s². All four kinematic equations apply to vertical motion independently.

The shared variable connecting both axes is time (t). Solve for t on one axis, then substitute it into the other. Our 2D kinematics solver handles both axes simultaneously, clearly labeling each component block.

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Expert Class Help

Sign Conventions: The Silent Grade Killer

More PHYS 1401 students lose points on sign errors than on conceptual misunderstandings. Establishing a consistent sign convention before every problem is non-negotiable:

  • Define rightward and upward as positive (standard in most textbooks and WebAssign physics lab modules).
  • If an object decelerates while moving in the positive direction, acceleration is negative.
  • Displacement is a vector: a car that returns to its starting point has Δx = 0, not the total distance traveled.
  • For free fall, always enter a = −9.8 m/s² (not +9.8), unless your problem explicitly defines downward as positive.

Common Kinematics Problem Types in PHYS 1401 and WebAssign

  • Braking/stopping distance: Given initial velocity and deceleration, find stopping distance. Known: v₀, v = 0, a (negative). Use Equation 3.
  • Free fall from rest: Object dropped from height h. Known: v₀ = 0, a = −9.8, Δy = −h. Use Equation 2 to find time, Equation 1 for impact velocity.
  • Rocket launch: Object launched upward. Find maximum height (where v = 0). Use Equation 3.
  • Projectile range: Launched at angle θ. Decompose into v₀ₓ = v⋅cos(θ), v₀ₑ = v⋅sin(θ). Solve vertical for time of flight, substitute into horizontal for range.
  • Uniform acceleration from rest: Car accelerates from 0. Known: v₀ = 0, a, t. Use Equations 1 and 2.

When a Kinematics Solver Is Not Enough: Professional Academic Support

Physics is one of the most demanding STEM courses in any degree program. Students in PHYS 1401, University Physics I, or AP Physics C often discover that the sheer volume of problem sets — combined with overlapping deadlines from chemistry labs, calculus homework, and engineering design projects — makes it genuinely impossible to keep pace. Many students in this situation search for options like “pay someone to take my online class for me” or “hire someone to take my online class for me” not out of laziness, but out of genuine academic pressure.

Our platform connects students with verified, subject-matter-expert academic professionals who can take over an entire online physics course, including WebAssign homework modules, lab report submissions, proctored quizzes, and midterm and final examinations. Every engagement is handled with absolute discretion, personalized academic strategy, and a grade guarantee that we define together before any work begins.

If you are currently struggling with your PHYS 1401 WebAssign physics lab, falling behind on kinematic problem sets, or staring down a final exam with no study time, the decision to pay someone to take my online class is a pragmatic one. Our experts have deep familiarity with WebAssign, Connect, Pearson MyLab, Cengage MindTap, and Canvas-hosted physics courses at hundreds of U.S. universities and community colleges.

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FAQ

Frequently Asked Questions About the Kinematics Solver

A kinematics solver takes 3 of the 5 kinematic variables (v₀, v, a, t, Δx) as input, identifies the correct kinematic equation, and algebraically solves for the missing values. Our solver displays each step — equation selection, value substitution, and algebraic isolation — mirroring what a professor would show on a whiteboard.

The solver uses all four standard equations: (1) v = v₀ + at, (2) Δx = v₀t + ½at², (3) v² = v₀² + 2aΔx, and (4) Δx = ½(v₀ + v)t. See the “Equation Reference” tab for the full decision matrix.

Yes. The step-by-step format matches the derivation structure expected in WebAssign physics lab reports. Use “Copy Solution” to export the full derivation. The tool is 100% client-side and works during timed WebAssign sessions.

Switch to “2D Projectile” mode. Enter horizontal (x) and vertical (y) variables separately. The horizontal component uses a = 0. The vertical component uses aₑ = −9.8 m/s². Time (t) is shared between both axes.

Yes. Our service allows students to pay someone to take their online physics class, including PHYS 1401 and WebAssign-hosted courses. Our certified physics experts handle the full coursework with complete discretion and a grade guarantee. Contact us for a free consultation.

The solver assumes SI units: meters (m) for displacement, meters per second (m/s) for velocity, meters per second squared (m/s²) for acceleration, and seconds (s) for time.

This means fewer than 3 fields have been filled in with valid numbers. You must provide at least 3 of the 5 kinematic variables. Double-check that each entered value is a valid number, not blank or text.

Yes. All inputs are treated as signed quantities. Enter negative velocity for motion in the negative direction, negative acceleration for deceleration when moving in the positive direction. The solver carries the sign correctly through every step.