interesting problems

general questions from various technical festivals
1.Build a human powered mechanical device which collects stones of varying sizes spread

over a solid ground
2.Build a small vehicle that runs on a flat surface and that it derives energy from earths

gravity only .Other forms of energy like rubber bands springs etc will not be allowed
3.Design and build a mechanical device to compare densities of two given solid objects of

unknown volume and masses.
4.Mechanical calculator that adds the numbers 0 to 9 and subtracts 0-9 and multiplication upto 5
5.Sine wave generator - genreate a sine wave by just giving a vertical force input
6.Make a system where there are will be maximum number of different forms of energy transfer takes place.

7.Build a device that collects the chips formed during the machining operation.So that the surroundings of the machine will be clean and the chips can be easily garbaged

8.Build a device which can pack gifts. Now a days we are seeing that the gift shops are very rush. So to save their time in packing the gift ....can we just make a device that can pack the gifts.

9.We used to see many spinners in the cricket. Can we make a machine that can spin the ball ????????????.A pure mechanical gadget that can spin the ball with some angle .