Rotational Motion: Can 1 Force Make It?

In summary, a free body can experience rotational motion due to a single force, but it will not be purely rotational. If the force is applied through the center of mass, the motion will be purely linear. Otherwise, the motion will be a combination of rotation about the center of mass and linear motion. To achieve pure rotation, the force must be divided into a "couple" and a force through the center of mass. This allows for the correct change in momentum and energy. While an unbalanced free body will initially move towards the applied force, sustained cyclic motion has not been demonstrated.
  • #1
nkehagias
3
0
It is possible for a free body to make rotational motion with the effect of one only force?
 
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  • #2
Not "pure" rotational motion. If the single force happens to be through the center of mass then you would get pure linear motion. If the single force is applied on a line not through the center of mass, then you will get a combination of rotation about the center of mass and linear motion. You would need to divide the force into a "couple"- a pair of equal but oppositely directed forces (so they add no linear motion) equally spaced about the center of mass to create the rotation- and a force through the center of mass to create the linear motion. You would need to set the forces so that the change in total momentum and energy is correct for the force applied.
 
  • #3
An unbalanced free-body will tend to rotate or otherwise move towards its attractive force. But this is only temporary(until balance is achieved). Sustained peak cycling of this has never been demonstrated to my knowledge.
 

1. What is rotational motion and how is it different from linear motion?

Rotational motion is the movement of an object around an axis or fixed point. It is different from linear motion because the object moves in a circular or curved path instead of a straight line.

2. Can one force cause rotational motion?

Yes, one force can cause rotational motion as long as it acts on an object at a distance from its center of mass, creating a torque or rotational force. This torque causes the object to rotate around its center of mass.

3. How does the direction of the force affect rotational motion?

The direction of the force affects the direction of the resulting rotational motion. For example, if the force is applied perpendicular to the axis of rotation, it will cause the object to rotate in a plane perpendicular to the force. If the force is applied at an angle, it will cause the object to rotate in a tilted plane.

4. Can multiple forces acting on an object cause rotational motion?

Yes, multiple forces acting on an object can cause rotational motion. The total torque on the object is the sum of all the individual torques from each force. As long as the net torque is not zero, the object will experience rotational motion.

5. How is rotational motion measured?

Rotational motion is measured using a unit called radians, which is a measure of the angle of rotation. One radian is equal to the angle subtended by an arc of length equal to the radius of the circle. The number of radians an object rotates is directly proportional to the distance traveled along the circular path.

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