does a larger wheel on a cart rolling down an incline increase or decrease the velocity?

Question

i am building a smal vehicle for an engineering project. i am using two sets of wheels, very small ones, (less than an inch in diameter) and very large ones (compact discs), which wheels are supposed to make it roll down an incline faster?

Answer 1

The larger wheels will be less inclined (excuse the pun) to slow down when they make contact with surface imperfections. Hence the larger wheels will allow a higher velocity than the smaller wheels. The down side is that the larger wheels are harder to make run true, which is crucial.

Answer 2

When a car is rolling down an incline, it is converting potential energy into kinetic energy. The kinetic energy takes two forms: that of the car moving forward and that of the wheels spinning. You want to maximize the first and minimize the second.

The mass moment of inertia for the wheels is proportional to r^4 (mass increases with r^2 and inertia increases with r^2 from the geometry). Of course your angular velocity goes down with the larger wheels, so the kinetic energy goes down by r^2. The net effect is that the wheels soak up energy by r^2.

Energy also goes out with friction, and on that score, the larger wheels are better.

I would go with the larger wheels to reduce friction, but take out as much weight as possible to minimize the amount of energy required to spin them. Leave a hub and a narrow tire and cut out thin spokes. You might want to do it with a machine tool to keep things in balance.

Answer 3

Check your M.E. handbook but smaller wheels have higher rolling friction than larger diameter wheels. This is of course assuming that the wheels are made of the same material.

Answer 4

The smaller ones. Larger wheeles have more mass to move so require more force.

Answer 5

Your loose physique diagram looks superb. For section 2, you have got a friction rigidity. It would not harm to attraction to yet another loose physique diagram as you probably did in part a million, yet comprise the friction rigidity opposing the action of the cart. The friction rigidity is comparable to the traditional rigidity circumstances the coefficient of friction. remember that f = ma, from the loose-physique diagram you will desire to have the skill to confirm the recent acceleration of the cart.

Answer 6

The larger ones, when they build up speed it will move faster.