# Weight on wheels to keep from spinning wildly

• TimNJ
In summary, to move a 2kg object 3 feet with a motor rated at 5000 RPM, the cart would need to be at least 2.6 kilograms (5.5 pounds) in weight.

#### TimNJ

Hello,

I'm working on my first year engineering project. I'm an electrical engineering major but this is a general engineering course.

I'd like to know how I could figure out how much weight I would need to put on the wheels of a cart that is going to push a 2kg object (for about 3 feet).

The motor will apply 2.6N of force in the x direction with wheels that are r=0.05m. The motor is capable of 5000RPM at full speed, but they can operate a low RPM for a short amount of time with higher torque, which is how I got the 2.6N figure. However, if the cart is too light, the wheels will just spin wildly and not move the 2kg object anywhere. How much weight would the cart need to be to get the book to move?

Thanks!

What! Were they all out of 10,000 RPM motors?

You haven't provided a lot of information about your cart. Please say you aren't driving the wheels 1:1 with the motor speed.

If you are driving 1:1, you could probably stand on your cart and the wheels would still spin. If you can't develop enough friction between the wheels and the driving surface, the wheel will spin uselessly. Even if the wheels grabbed, it's possible your cart would shoot out across the room out from under the book. Inertia, you know.

If you can't find a slower motor, at least try to put some speed reduction between the motor and the wheels. If you had gears with, say, a 10:1 reduction, not only would the speed at the wheels drop but the torque would be multiplied by 10.

It would be wise to make the cart somehow wedge itself under the object. That could transfer load to the driving wheels and reduce the object's friction with the surface.

SteamKing said:
If you can't develop enough friction between the wheels and the driving surface, the wheel will spin uselessly.
Correct.

If you can't find a slower motor, at least try to put some speed reduction between the motor and the wheels. If you had gears with, say, a 10:1 reduction, not only would the speed at the wheels drop but the torque would be multiplied by 10.
Not correct.

If the coefficient of friction of the wheels is less than that of the book, the wheels will always spin regardless of the reduction. First determine the two coefficients of friction. Then calculate how much weight you need to add to the car to increase its coefficient of friction to more than that of the book. Note: The running coefficient of friction for the car must be greater than the breakaway coefficient for the book.

I agree but all that torque is wasted unless the car can get enough traction to overcome the friction of the book.

skeptic2 said:
I agree but all that torque is wasted unless the car can get enough traction to overcome the friction of the book.

I believe the cart is supposed to carry the book, so I don't know what your statement means.

Wheeled vehicles function at all because there exists a high coefficient of friction between the wheels and the road surface (especially railroads). On icy or wet surfaces, the coefficient of friction is greatly reduced and travel is impeded because the wheels cannot get traction.

SteamKing said:
I believe the cart is supposed to carry the book, so I don't know what your statement means.

TimNJ said:
I'd like to know how I could figure out how much weight I would need to put on the wheels of a cart that is going to push a 2kg object (for about 3 feet).

Bolding mine.

Hello everyone,

I have read all of your responses and they are very helpful. I am absolutely loaded with schoolwork for the next 48 hours so as much as I want to make a meaningful response, I reallly need to focus on my work due in the near future.

To answer a question or two, I was initially thinking of using 1:1, but that seems rather foolish now that I think of it. Even if the rest of it is worked out correctly on paper, if the wheels don't stay on the ground it's useless.

I'm going to look up how gearing works. I'm a freshman electrical engineering student after all. Haha.

And yes for this project, I *think* pushing would be the most effective but I'm not sure.

Thanks.

## 1. How does weight on wheels help prevent spinning wildly?

Weight on wheels is a concept used in vehicles to help maintain stability and prevent spinning. When weight is evenly distributed on all four wheels, it helps to keep the vehicle balanced and prevents it from tipping or spinning out of control.

## 2. What factors affect weight on wheels?

There are several factors that can affect weight on wheels, including the weight of the vehicle, the distribution of weight within the vehicle, and the road conditions. A vehicle with a higher center of gravity, such as an SUV, may have a higher risk of spinning wildly if weight is not properly distributed.

## 3. Why is weight distribution important for vehicles?

Weight distribution plays a crucial role in maintaining stability and preventing accidents in vehicles. Uneven weight distribution can cause a vehicle to become imbalanced, making it more prone to spinning wildly or tipping over. It is important to properly distribute weight for safe driving.

## 4. How does a vehicle's weight affect its handling?

The weight of a vehicle can greatly impact its handling and stability. A heavier vehicle may be more difficult to control and may have a higher risk of spinning wildly. On the other hand, a lighter vehicle may be more responsive and easier to maneuver, but may have a higher risk of tipping over.

## 5. Can weight on wheels be adjusted?

In some vehicles, weight on wheels can be adjusted through various methods such as shifting cargo or adjusting suspension settings. However, it is important to consult with a professional before making any modifications to the weight distribution of a vehicle to ensure safety and proper handling.