Home › A-Level 9702 › Forces, density and pressure
AS · Topic 4

Turning, balancing and floating.

The moment of a force and the couple that turns without pushing, the conditions that hold a body in equilibrium when three forces meet, and the first encounter with fluids where hydrostatic pressure gives Archimedes' upthrust. Play the three simulations below to feel the balance points and the buoyant force for yourself. The gamified lessons, the topic Paper 1 practice and the concept map are all live below too.

Simulations · live
Interactive · live The turning effect of a force Slide the load along the beam and watch the moment grow as M = F × d, then balance the clockwise and anticlockwise turns. Loads only when you launch, so the page stays fast.
Interactive · live Three forces in equilibrium Adjust three coplanar forces on a point and watch the vector triangle close head-to-tail when the resultant reaches zero. Loads only when you launch, so the page stays fast.
Interactive · live Density, pressure and upthrust Lower a block into the fluid and watch the hydrostatic pressure climb with depth while the upthrust F = ρgV decides whether it floats or sinks. Loads only when you launch, so the page stays fast.
Paper 1 practice · live
Multiple choice · Paper 1 style Topic Paper 1 practice questions A full topic set of original multiple-choice questions across moments, equilibrium, density and upthrust, with instant marking. Open practice →
Lessons · live
Turning effects of forces: moments and couples → Equilibrium of forces and the principle of moments → Density, pressure and Archimedes' principle →
Concept map
Open the concept map →