# Torque question need explaination

• MikeMai
In summary, it is possible to calculate torque without specifying an origin, however, the torque is dependent on the location of the origin. If the mouse is walking around the perimeter of the table, the horizontal turntable will move in a counterclockwise direction.
MikeMai

## Homework Statement

1.Is it possible to calculate the torque acting on a rigid object without specifying an origin? Is the torque independent of the location of the origin?

2.A mouse is initially at rest on a horizontal turntable mounted on a frictionless vertical axle. If the mouse begins to walk clockwise around the perimeter of the table, what happens to the turntable? Explain using Newton's Laws.

## Homework Equations

No,equation. Need to explain in words.

## The Attempt at a Solution

for #1 i put no, we can't find torque without a specifying an origin since we won't know the length. But i don't get the 2nd part about the independent thing.

for #2 i put,
If the mouse is initially at rest on a horizontal turntable and walks at a clockwise direction, then the horizontal turntable will move in a counterclockwise direction. Using Newton's third law, the mouse is walking and does not accelerate so all the forces equals zero. Since all the forces equals to zero that means the forces the turntable exerts back the equal but opposite force back to the mouse.

MikeMai said:

## Homework Statement

1.Is it possible to calculate the torque acting on a rigid object without specifying an origin? Is the torque independent of the location of the origin?

2.A mouse is initially at rest on a horizontal turntable mounted on a frictionless vertical axle. If the mouse begins to walk clockwise around the perimeter of the table, what happens to the turntable? Explain using Newton's Laws.

## Homework Equations

No,equation. Need to explain in words.

## The Attempt at a Solution

for #1 i put no, we can't find torque without a specifying an origin since we won't know the length. But i don't get the 2nd part about the independent thing.

for #2 i put,
If the mouse is initially at rest on a horizontal turntable and walks at a clockwise direction, then the horizontal turntable will move in a counterclockwise direction. Using Newton's third law, the mouse is walking and does not accelerate so all the forces equals zero. Since all the forces equals to zero that means the forces the turntable exerts back the equal but opposite force back to the mouse.

It depends in what are you trying to calculate...

*As you know, torque is a vector, so, as a vector it has magnitude and direction. If you try to find $$\overrightarrow{\tau}$$ the vector you have:

$$\overrightarrow{\tau}=\overrightarrow{r}\times \overrightarrow{F}$$

r: position vector F: force vector

In this case, you need a reference system

*If you are trying to find magnitude you have to calculate $$|\overrightarrow{\tau}|$$(usually in basic physics known as $$|\tau|=|r|\cdot |F|\cdot |\sin \theta|$$), in this case, you only need the $$F_{\perp}$$ at the point you're interested in and the distance to the axis of turning, there's no need to put an origin.

Sometimes the problems with torque has lot of forces or asks for angular acceleration, so in this cases you need to work with them as vectors to get all the information.

I apologize if you don't understand something, my english isn't so advanced, I hope you understand... greetings!

Thank you for trying, those are the exact questions they asked me. So yeah...I need answer for the 2nd part of question #1, and confirmation of #2...

Would greatly appreciated if someone can help me out before midnight, 1h 30min left.

## 1. What is torque and how is it measured?

Torque is a measure of the rotation of an object around an axis. It is measured in units of Newton-meters (Nm) or foot-pounds (ft-lb). It can be calculated by multiplying the force applied to an object by the distance from the axis of rotation.

## 2. What is the difference between torque and force?

While both torque and force are measures of the interaction between two objects, they differ in their direction and effect. Force is a push or pull in a straight line, while torque is a rotational force. Force is measured in units of Newtons (N) or pounds (lb), while torque is measured in units of Newton-meters (Nm) or foot-pounds (ft-lb).

## 3. How does the point of application affect torque?

The point of application of a force affects the torque it produces. If the force is applied closer to the axis of rotation, it will produce a smaller torque. On the other hand, if the force is applied farther from the axis of rotation, it will produce a larger torque.

## 4. Can torque be negative?

Yes, torque can be negative. This occurs when the force and distance vectors are in opposite directions, causing the object to rotate in the opposite direction. Negative torque is also known as "counterclockwise torque" while positive torque is known as "clockwise torque".

## 5. How is torque used in everyday life?

Torque is used in many everyday activities, such as opening a door, using a wrench to loosen a bolt, and riding a bike. It is also an important concept in engineering and mechanics, as it helps determine the stability and strength of structures and machines.

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