Circumference and arc length

  • Rollin' Rollin' Rollin'
    problem

    Rollin' Rollin' Rollin'

    Age
    11 to 14
    Challenge level
    3 out of 3

    Two circles of equal radius touch at P. One circle is fixed whilst the other moves, rolling without slipping, all the way round. How many times does the moving coin revolve before returning to P?

  • Contact
    problem

    Contact

    Age
    14 to 16
    Challenge level
    2 out of 3
    A circular plate rolls in contact with the sides of a rectangular tray. How much of its circumference comes into contact with the sides of the tray when it rolls around one circuit?
  • Small pepper seedlings in turquoise pots.
    problem

    Rolling Inside

    Age
    14 to 16
    Challenge level
    2 out of 3

    Weekly Problem 11 - 2007
    A circle of radius 1 rolls without slipping round the inside of a square of side length 4. Find an expression for the number of revolutions the circle makes.

  • Just rolling round
    problem

    Just Rolling Round

    Age
    14 to 16
    Challenge level
    3 out of 3

    P is a point on the circumference of a circle radius r which rolls, without slipping, inside a circle of radius 2r. What is the locus of P?

  • Giant Holly Leaf
    problem

    Giant Holly Leaf

    Age
    14 to 16
    Challenge level
    3 out of 3
    Find the perimeter and area of a holly leaf that will not lie flat (it has negative curvature with 'circles' having circumference greater than 2πr).
  • Small pepper seedlings in turquoise pots.
    problem

    Roll On

    Age
    14 to 16
    Challenge level
    3 out of 3

    Weekly Problem 5 - 2006
    How many times does the inside disc have to roll around the inside of the ring to return to its initial position?

  • Small pepper seedlings in turquoise pots.
    problem

    Running Race

    Age
    14 to 16
    Challenge level
    3 out of 3

    Weekly Problem 13 - 2006
    If three runners run at the same constant speed around the race tracks, in which order do they finish?

  • Five circuits, seven spins
    problem

    Five Circuits, Seven Spins

    Age
    16 to 18
    Challenge level
    2 out of 3
    A circular plate rolls inside a rectangular tray making five circuits and rotating about its centre seven times. Find the dimensions of the tray.
  • Over The Pole
    problem

    Over the Pole

    Age
    16 to 18
    Challenge level
    3 out of 3
    Two places are diametrically opposite each other on the same line of latitude. Compare the distances between them travelling along the line of latitude and travelling over the nearest pole.