question.rb1 question :a_whirled_stone do2   kind :numerical3   describes "A stone on a string is whirled round a horizontal circle at a steady speed. The string is %{length} long, and the stone makes %{turns} turns in %{time}. %{acceleration}, in m/s²?"4   given length: "80 cm"5   given turns: 14.06   given time: "25 s"7   asks acceleration: "What is its acceleration"8 end

solution.rb1 solve :a_whirled_stone, using: UniformCircularMotion do2   objects :stone3   paths :circle4   stone.goes(:round, on: circle)5   take length: circle.radius, turns: stone.revolutions, time_taken: stone.goes.time_taken6   acceleration = stone.centripetal_acceleration7   answer acceleration:, in: "m/s2", figures: 38   conclusion "The stone moves at a steady speed but its direction changes constantly, so it has a centripetal acceleration toward the centre of the circle."9 end