# Torque Help -- Tension in a Hoist Cable

• smr101
In summary, the conversation discusses a problem with calculating the angular acceleration and power for a drum with given frictional torque and dimensions. The solution involves first calculating the angular acceleration and then using an equation to relate torque and angular velocity. The final power calculation is two times the torque.
smr101
Hi, I'm having a problem with 3. (b) (ii) here.

I know that the frictional torque is 1500Nm and that from (b)(i) being 5055N I assume this is multiplied by 1.5M (drum shaft radius) which gives me 7582.5N. Do I have to calculate the angular acceleration of the drum from here, which could then give me the torque? And if so, how?

Help much appreciated. Answer and solution below.

In addition to this how is the power calculated for (b)(iii)? I understand it is two times the torque but why?

Thanks.

Two times the torque?

Power = Torque * angular velocity

Hi, I'm having a problem with 3. (b) (ii) here.
I know that the frictional torque is 1500Nm and that from (b)(i) being 5055N I assume this is multiplied by 1.5M (drum shaft radius) which gives me 7582.5N. Do I have to calculate the angular acceleration of the drum from here, which could then give me the torque? And if so, how?

Yes.

First calculate the angular acceleration from the velocity of the rope and the dimensions of the drum.

Then what equation relates torque and angular velocity?

Last edited:
PS: The Torque will not be the value calculated earlier because part iii) says "at a constant speed".

## What is torque?

Torque is a measure of the rotational force or the ability of a force to produce a rotational motion. It is calculated by multiplying the force applied by the perpendicular distance from the point of rotation.

## What is tension in a hoist cable?

Tension in a hoist cable refers to the pulling force that is exerted on the cable when lifting a load. It is important to properly calculate and maintain tension in a hoist cable to ensure safe and efficient lifting.

## How does torque affect tension in a hoist cable?

Torque and tension in a hoist cable are directly related. As the torque increases, the tension in the cable also increases. This means that a larger load or a longer distance from the point of rotation will require a higher torque and therefore a higher tension in the cable.

## What are the factors that affect torque and tension in a hoist cable?

There are several factors that can affect torque and tension in a hoist cable, including the weight of the load, the length of the hoist arm, the angle of the hoist arm, and the coefficient of friction between the cable and the pulley.

## How can torque and tension in a hoist cable be calculated?

To calculate torque and tension in a hoist cable, you will need to know the weight of the load, the distance from the point of rotation, and the angle of the hoist arm. From there, you can use the formula: torque = force x distance and tension = torque / radius of the hoist arm.

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