Hello June78

Welcome to Math Help Forum! We are asked to start to record the height of the stone as soon as it becomes stuck. So at , the height is cm - the stone is still at ground level.

After revolution , the stone will be level with the centre of the wheel, so it will be cm above the ground.

Continue in the same way. At it will be at the top of the wheel, so it's ...? cm above the ground.

When you come to sketch the graph, you'll need to consider 2 complete revolutions of the wheel. You'll get a graph similar to the ones here.

Grandad