Kinematics in MotionRIGID-BODY KINEMATICS
TEXTBOOK PROBLEMS, BROUGHT TO LIFE
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PAUSEDt = 0.000 s
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Click a joint or a body to inspect it
Velocity vAcceleration a
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Motion inputs

Default inputs
FOLLOW THE NUMBERS

Point history

Click or drag a plot to scrub time
Velocity
Acceleration

All labeled points

Current instant
PointVelocity components|v|Acceleration components|a|
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What to notice

aP = aO + α × r + ω × (ω × r)
The problem, equations & reference check Rigid-body model

Problem & motion model

Velocities and accelerations are evaluated from the constrained geometry and rigid-body formulas. Input acceleration defines the drive; animation speed changes only playback. Links are ideal rigid bodies. No force or flexibility model is implied.

At the reference snapshot

These checks use the original inputs, even while you explore other settings.

Explore motion, one point at a time.

01 · Choose an example

The sidebar contains nine distinct examples. Choose any example to explore its motion, velocity, and acceleration.

02 · Freeze any instant

Play, pause, step, enter an exact time, or drag the timeline. Click either chart to jump to that moment. “Reset example” restores the original inputs and illustrated configuration.

03 · Pick a material point

Click a labeled point or a rod. Use “Place a point” for a location along any link, inside a wheel, or on the sphere. That point stays attached to its body. For 3D scenes, drag to orbit; the view selector provides coordinate-plane views.

04 · Change the drive

Type a velocity or acceleration or use its slider. Values are signed in the directions shown. Initial values apply at t = 0; the sphere reaches the illustrated state later. A travel limit ends playback before a linkage becomes singular.

05 · Read the vectors

Cyan arrows show velocity; coral arrows show acceleration. Optional amber and violet arrows separate tangential and normal acceleration. Each quantity uses one fixed scale during playback, listed on the canvas. A dashed capped arrow means it exceeds the visible scale.

06 · Watch rolling contact carefully

A tracked point A or B is one material particle. K is the wheel particle currently touching the ground or belt; its identity changes with time. Its velocity can vanish while its upward acceleration remains nonzero. Its contact-location history is labeled accordingly.