# Finding the torque needed to accelerate a wheel

• Pablo
In summary, the torque required to accelerate an object of 50kg and radius 0.025m from 0 to 0.4 in 20s is 0.39 Nm.
Pablo

## Homework Statement

Object of fifty kg and a r= 0.025m. What's the torque to accelerate from 0 to 0.4 in 20s.

## Homework Equations

Torque = Moment of inertia * angular acceleration
T = I * α

## The Attempt at a Solution

[/B]
m = 50kg
r = 0.25m
α = (0.4) / 20 = 0.02

I = mr^2 = 50 * 0.25^2 = 3.125
T = I * α = 3.125 * 0.02 = 0.0625 Nm

I got 0.0625 Nm for my torque, but this does not match any of the choices. Am I doing something wrong?

Last edited:
Welcome to the PF.
Pablo said:
α = (0.4) / 20 = 0.02
The units for angular acceleration should be in radians/s^2. How many radians are there in one revolution?

BTW, it's a good idea to carry units along in your calculations. That helps you to see errors like that early and correct them along the way.

berkeman said:
Welcome to the PF.

The units for angular acceleration should be in radians/s^2. How many radians are there in one revolution?

Wow, I can't forgot to multiply by 2 pi, thanks! I got 0.39Nm :)

berkeman

## What is torque and how does it relate to accelerating a wheel?

Torque is a measure of the twisting force applied to an object. In the context of accelerating a wheel, torque is the force that causes the wheel to rotate. The amount of torque needed to accelerate a wheel depends on the mass of the wheel and the rate at which it needs to accelerate.

## How do you calculate the torque needed to accelerate a wheel?

The formula for calculating torque is torque = force x distance. In the case of accelerating a wheel, the force would be the force of the engine or motor that is powering the wheel, and the distance would be the radius of the wheel. So the torque needed to accelerate a wheel can be calculated by multiplying the force by the radius of the wheel.

## What factors affect the torque needed to accelerate a wheel?

The main factors that affect the torque needed to accelerate a wheel are the mass of the wheel, the rate of acceleration, and the resistance of the wheel's rotation. Additionally, the type of surface the wheel is on and the presence of any external forces, such as air resistance, can also affect the torque needed.

## How does the distribution of weight on a wheel affect the torque needed to accelerate it?

The distribution of weight on a wheel can significantly impact the torque needed to accelerate it. If the weight is evenly distributed around the wheel's axis of rotation, the torque needed will be lower compared to if the majority of the weight is located at the edge of the wheel. This is because the weight at the edge creates a larger moment arm, increasing the torque required to overcome it.

## Is there a maximum torque that can be applied to a wheel to accelerate it?

Yes, there is a maximum torque that can be applied to a wheel to accelerate it. This maximum torque is determined by the maximum torque that the wheel's axle and bearings can withstand without breaking. It is important to stay within this limit to prevent damage to the wheel and its components.

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