5 Written Questions
5 Matching Questions
- Stick about CG:
- rotational inertia
- a ¹Physics types usually describe rotational speed, ω, in terms of the number of "radians" turned in a unit of time. There are a little more than 6 radians in a full rotation (2π radians, to be exact). When a direction is assigned to rotational speed, we call it rotational velocity). Rotational velocity is a vector whose magnitude is the rotational speed. By convention, the rotational velocity vector lies along the axis of rotation.
- b In a machine, the ratio of useful energy output to total energy input, or the percentage of work input that is converted to work output.
- c the tendency of a force to rotate an object about an axis (force x lever arm)
- d I = 1/12 mL²
- e Reluctance or apparent resistance of an object to change its state of rotation, determined by the distribution of the mass of the object and the location of the axis of rotation or revolution.
5 Multiple Choice Questions
- When no external torque acts on an object or a system of objects, no change of angular momentum can occur. Hence, the angular momentum before an event involving only internal torques or no torques is equal to the angular momentum after the event.
- Point at the center of an objects mass distribution, where all its mass can be considered to be concentrated. For everday conditions, it is the same as the center of gravity.
- Inertia in motion. The product of the mass & velocity of an object (provided the speed is much less than the speed of light) has magnitude & direction & therefore is a vector quantity. Also called linear momentum & abbrieviated p=mv
- I = 1/3 mL²
- I = mr^2
where m = mass, r = distance, I = rotational inertia
5 True/False Questions
Axis → the straight line around which rotation occurs
Centrifugal ("Center-Fleeing") Force → This force is not an actual force; it is a fictitious force that seems to pull outwards on an object on a circular path. This effect is due to inertia, or the tendency for a moving object to follow a straight path.
Conservation of energy for machines → The work output of any machine cannot exceed the work input.
tangential speed → The linear speed tangent to a curved path, such as in circular motion.
Centrifugal force → The linear speed tangent to a curved path, such as in circular motion.