Equilibrium of rigid bodies
Rigid body dynamics · Physics
Simple pendulum
Interactive 3DRelease the bob and watch true small-angle SHM. The period depends only on the string length.
Controls
Drag the sliders or type a value — the simulation updates live.
Study notes
Let's look at a 2-meter long uniform rod resting on two supports at its ends. A 10 kg block is placed exactly at the middle (1 meter mark). Step 1: Identify forces. Gravity pulls the 10 kg block down (Weight = mass × gravity = 10kg × 9.8m/s² = 98 Newtons). Step 2: Set Translational Equilibrium. The two supports (let's call them R1 and R2) push up. So, R1 + R2 = 98 Newtons. Step 3: Set Rotational Equilibrium. We choose the left end as a pivot point. The weight is 1 meter away, creating a clockwise torque (98N × 1m = 98 Nm). The support R2 is 2 meters away, creating a counter-clockwise torque (R2 × 2m). For balance, 98 Nm = R2 × 2m. Step 4: Solve. R2 = 98 / 2 = 49 Newtons. Now, R1 + 49 = 98, so R1 = 49 Newtons. Both supports share the weight equally.