Question about two torques on rigid body.

In summary, the conversation discusses a massless, rigid rod with motors attached to each end, connected to massive discs that can be accelerated in different directions. The question is whether there will be a net torque or force on the rod and other disc due to the torque from the motors. Assuming there are no other forces, it is expected that the rod will rotate along with the discs about their common axis. When both discs are spun in the same direction, there will be a torque couple causing this rotation. However, in the case of the discs being spun in opposite directions, there will be torsion.
  • #1
Crappinni
3
0
Hi, here's the question:

A massless, rigid rod has motors attached on each end. The motors are each connected to a massive disc, and the motors accelerate the discs in the directions indicated by the arrows.

Due to the torque from the each motor on its disc and hence that on the rod and other disc, is there a net torque or force?

Assuming there are no other forces (like gravity or friction), what will happen?

Additionally, if both discs are spun in the same direction, what happens?

Thanks!
 

Attachments

  • question.jpg
    question.jpg
    15.5 KB · Views: 329
Physics news on Phys.org
  • #2
Bump! Please help!
 
  • #3
What do you expect to happen?
Clearly, the rod will rotate along with the discs about their common axis.
 
  • #4
R Power said:
What do you expect to happen?
Clearly, the rod will rotate along with the discs about their common axis.

Thanks for answering.

I'm sure that's the case when both discs are spun the same way because of the torque couple. But when they are spun in opposite directions, why would they have a common axis?
 
  • #5
I'm sure that's the case when both discs are spun the same way because of the torque couple. But when they are spun in opposite directions, why would they have a common axis?
in case discs are spun in opposite directions there will be the case of torsion.
 

1. What is a rigid body?

A rigid body is an object that does not deform or change shape under the action of external forces. This means that all points on the object maintain the same distance and orientation relative to each other.

2. What are torques?

Torques are a type of force that causes rotational motion in an object. They are typically measured in units of Newton-meters (Nm) and are calculated by multiplying the force applied to an object by the distance from the point of rotation.

3. How are two torques applied to a rigid body?

Two torques can be applied to a rigid body in several ways. They can act in the same direction, reinforcing each other, or they can act in opposite directions, canceling each other out. They can also act at different points on the object, resulting in a net torque that causes rotational motion.

4. What is the equation for calculating the net torque on a rigid body?

The net torque on a rigid body is calculated by multiplying the force applied to the object by the distance from the point of rotation, and then summing the torques from each force. This can be represented by the equation Στ = F * r.

5. How does torque affect the rotational motion of a rigid body?

Torque determines the rate of rotational motion of a rigid body. The larger the torque, the faster the object will rotate. Additionally, the direction of the torque will determine the direction of rotation, with counterclockwise torques causing counterclockwise rotation, and vice versa.

Similar threads

Projectile motion of a two-point rigid body
    • Mechanics
Replies
8
Views
1K
Confusion About Rotational Motion
    • Mechanics
Replies
19
Views
1K
A rotating system of two point particles with inner torque
    • Mechanics
Replies
1
Views
711
I Conservation of angular momentum during collisions
    • Mechanics
Replies
3
Views
1K
Reaction torque in a traction system
    • Mechanics
Replies
10
Views
1K
Question about torque and center of mass
    • Mechanics
Replies
6
Views
2K
Where on a rigid body is a resultant force applied?
    • Introductory Physics Homework Help
Replies
11
Views
225
Torque Production in Eddy Current Motors
    • Electrical Engineering
Replies
18
Views
2K
I Understanding Net Internal Torque and Kinetic Friction in a System
    • Mechanics
Replies
9
Views
1K
I Solving Wheel Coming to a Stop: FBD, Friction & Hysteresis
    • Mechanics
Replies
22
Views
2K

Hot Threads

Recent Insights

Back
Top