Find the balance point
The centre of mass weights each position by its mass. A uniform rod contributes its own midpoint. Move either particle or change its mass to move the balance point toward the heavier side.
Run this experiment →Physics · Class 11
Particles & Rotational Motion
10 free physics experiments and lesson notes for Particles & Rotational Motion, with model limits, worked examples and Tamil explanations.
Follow a collision centre
Internal collision forces change the carts individually, while their centre of mass continues along a straight line at a constant velocity. The sticking collision dissipates kinetic energy but conserves momentum.
Run this experiment →Move the force lever
Torque measures the turning effect of a force. Only its component perpendicular to the lever turns the body. A force along the lever produces zero torque even when its magnitude is large.
Run this experiment →Pull rotating masses inward
With no external torque, angular momentum remains constant. Bringing mass closer to the rotation axis reduces inertia and increases angular speed. The pulling mechanism supplies the extra kinetic energy.
Run this experiment →Can the ladder stay balanced?
Taking moments about the foot determines the horizontal wall reaction. The floor must provide equal horizontal friction and support the weight. A steeper ladder needs less friction in this ideal model.
Run this experiment →Accelerate a rotating wheel
A constant net torque gives constant angular acceleration for a body with fixed inertia. The rotational equations mirror constant-acceleration linear motion, with torque replacing force and inertia replacing mass.
Run this experiment →Compare shapes around an axis
Moment of inertia depends on how mass is distributed relative to an axis. More mass farther from the axis increases I. Radius of gyration is the single effective radius that reproduces I= Mk².
Run this experiment →Shift the rotation axis
Moving an axis parallel to the central axis adds Md² to inertia. For a thin planar body, the perpendicular-axis theorem adds two orthogonal in-plane inertias. These theorems refer to different axis relationships.
Run this experiment →Roll a ring, cylinder or sphere
Gravitational energy becomes both translational and rotational kinetic energy. Bodies with a smaller shape factor need less rotational energy per unit speed and accelerate faster. The no-slip condition is v=ωr.
Run this experiment →Strike a hinged rod
During a brief collision the hinge can exert an impulse, so linear momentum of particle plus rod need not be conserved. Its moment about the hinge is zero, allowing angular momentum about that point to determine the final rotation.
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