A2L Item 087
- Description: Specify the characteristics of the linear acceleration of a body having uniform angular acceleration.
- Goal: Hone angular kinematic quantities and distinguish them from linear kinematic quantities.
- Source: UMPERG
- Keywords: Acceleration, Angular Acceleration, Mechanics, Rotational Motion
The question for students:
A mass moves in a circle with uniformly increasing anglular velocity.
As the angular velocity ω increases, the linear acceleration of the mass has…
- constant magnitude and direction.
- constant magnitude, changing direction.
- changing magnitude, constant direction.
- both magnitude and direction changing.
Commentary for teachers:
Answer
(4) This requires exploration. Some students may think that the direction is changing because the acceleration points toward the center of the circle. They may be unaware that there is also a component of the acceleration in the tangential direction.
Some students may answer (3) thinking only of the radial acceleration and that ‘towards the center’ is a direction.