Download presentation

2
**Particle vs. Rigid-Body Mechanics**

What is the difference between particle and rigid-body mechanics? Rigid-body can be of any shape Block Disc/wheel Bar/member Etc. Can determine motion of any single particle (pt) in body particle Rigid-body (continuum of particles)

3
**Types of Rigid-Body Motion**

Kinematically speaking… Translation Orientation of AB constant Rotation All particles rotate about fixed axis General Plane Motion (both) Combination of both types of motion B A B A B A B A

4
**Kinematics of Translation**

B A y Kinematics Position Velocity Acceleration True for all points in R.B. (follows particle kinematics) rB rA x

5
**Rotation about a Fixed Axis – Angular Motion**

Point P travels in circular path (whether “disk” or not) Angular motion Angular position, θ Angular displacement, dθ Angular velocity ω=dθ/dt Angular Acceleration α=dω/dt r Axis of rotation

6
**Rotation about a Fixed Axis – Angular Motion**

Point P travels in circular path (whether “disk” or not) Angular motion Angular position, θ Angular displacement, dθ Angular velocity ω=dθ/dt Angular Acceleration α=dω/dt Angular motion Equations r Axis of rotation In solving problems, once know ω & α, we can get velocity and acceleration of any point on body!!! (next slide) (Or can relate the two types of motion if ω & α unknown )

7
**Rotation about a Fixed Axis – Motion of Point**

Point P travels in circular path Position of P Defined by r If body rotates some dθ, then displacement is ds = r dθ Velocity (tangent to path) Acceleration (2 components) r an ∆v v a ∆v a an at an v

8
Example Problem When the gear rotates 20 revolutions, it achieves an angular velocity of ω = 30 rad/s, starting from rest. Determine its constant angular acceleration and the time required. (F16-1, 3.58 rad/s2, 8.38 s)

9
Example Problem The gear A on the drive shaft of the outboard motor has a radius of rA = 0.5 in and the meshed pinion gear B on the propeller shaft has a radius rB = 1.2 in. Determine the angular velocity of the popular in t = 1.5 s, if the drive shaft rotates with an angular acceleration a = (400t3) rad/s2 , where t is in seconds. The propeller is originally at rest and the motor frame does not move.

Similar presentations

OK

Rotational Kinematics Chapter 8. Expectations After Chapter 8, students will: understand and apply the rotational versions of the kinematic equations.

Rotational Kinematics Chapter 8. Expectations After Chapter 8, students will: understand and apply the rotational versions of the kinematic equations.

© 2018 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on internet banking project Ppt on power grid india Ppt on gir national park Ppt on history of australia colony Ppt on word association test in psychology Ppt on brand marketing jobs Ppt on paintings and photographs related to colonial period in america Ppt on index of industrial production of india Project ppt on library management system Collaborative strategic reading ppt on ipad