Lecture 8 - Linear vs. Angular Kinematics

Question 1

The arc (distance travelled) depends on what?

Answer 1

The arc (distance travelled) depends on how far away you are from the axis of rotation

Question 2

Although every part of an object moving about an axis has the same angular distance, each part of the object has a different ____________________

Answer 2

linear distance

Question 3

Linear distance =

Answer 3

radius between axis and point x angle

Question 4

REVIEW “Linear vs. Angular Motion” SECTION FOR LINEAR DISTANCE FORMULA

Question 5

REVIEW “Linear vs. Angular Velocity” SECTION FOR LINEAR VELOCITY FORMULA

Question 6

In baseball batting, where would you want the ball and bat to make contact? Why?

To calculate…

Answer 6

At the tip, because this is the fastest point on the bat

In order for the ball to have a large initial velocity, it would need to make contact with the tip of the bat, because this area is going fastest (has a large velocity)

➢ Take the angular velocity and multiply it by the radius
➢ Make sure the angular velocity is in radians/sec, not degrees
➢ Make sure the radius is in meters
➢ Final units should be meters/sec

Question 7

The acceleration of a body in angular motion can be resolved into….

Answer 7

two perpendicular linear acceleration components

To add tangential and radial acceleration, use pythagorean theorem (a^2 + b^2 = c^2);
this answer should be a greater number than the other numbers in the equation, because the hypotenuse is the longest side

Question 8

Tangential acceleration (at):

*FORMULA IN LECTURE NOTES

Answer 8

➢ 90 degrees to the radius

➢Speeding up as it goes around the radius, or axis of rotation

➢Component of acceleration of angular motion directed along a tangent to the path of motion

➢Represents change in linear speed over time

➢ r x angular acceleration = tangential linear acceleration

Question 9

Radial acceleration (ar):

*FORMULA IN LECTURE NOTES

Answer 9

➢ The acceleration needed to change the direction

➢ Component of acceleration of angular motion directed toward the centre of curvature

➢ Represent a change in direction (once something is released, like a ball, there is no more radial acceleration)

➢ This will be instantaneous