How do I make a Joule Mobile?!?

Question

It MUST travel a distance of 4 meters.
It can not be taller than 19 inches.
It can not be longer than 14 inches.
Please help! With as much detail as possible!

Answer 1

Joule mobile constraints

S= 4m
H= 19x 2.54=48.26 cm (48)
L= 14 x 2.54 = 35.56 cm (35)


In a joule mobile, if I understand correctly, we must transform potential energy of mass located on a machine. to make that machine move linearly on a leveled surface.

Let's say we build a frame with a pulley on top and mount it on 4-wheeled platform. We wrap a string about one of its axles then over a pulley and attach a weight of mass M. As we release this mass it will force the axle to rotate and that will force the contraption to move.( Hopefully 4 m)

The total height of the machine must not exceed H = 48cm then let the vertical travel be 44 cm . (We need some space for the upper pulley(s) and minimum distance from center of mass M and pulley ) Then potential energy maximum is
Pe= Mgh

We have to use that energy to move your joule machine. Some energy will be used to accelerate (overcome the inertia) of the contraption, but most of the energy is used to overcome the forces of friction.

Let me know if you need further information.