A worker uses a long metal bar as a lever to lift one edge of a heavy stone.
The bar rests on a small block, which acts as the pivot.
The worker pushes down on one end of the bar with a force of 150 N, at a distance of 1.2 m from the pivot.
The other end of the bar is under the stone, 0.15 m from the pivot.
Assume that all the forces act at right angles to the bar.
Calculate the moment of the worker's force about the pivot.
Calculate the force that the bar exerts on the stone.
Explain how the bar allows the worker to lift the stone with a small force.
The worker now pushes down on the bar at a distance of 0.60 m from the pivot.
State the force the worker must now apply to exert the same force on the stone.
102 exam-style questions on Edexcel GCSE Physics 9.2 Moments, covering 9.2.1 Rotational effects of forces and moments, 9.2.2 The principle of moments, and 9.2.3 Levers and gears. Each one has a worked solution and a mark scheme showing where the marks go.