Question

7. The rod CD is rotating with an angular velocity cp = 2 rad/s. Determine: i) The velocity of point C and show its direction in the figure below ii) What is the angular velocity of link BC? iii) What is the velocity of points B and E? iv) What is the angular velocity of link AB? (30 points) 0.2 m 0.2 m B E 0.4 m 30° Wcp= 2 rad/s А. D

Answer 1

Given: Length of link CD, r = 0.4m

$\omega _{CD}=2rad/s$

Velocity of link CD = $r\omega = 0.4*2=0.8m/s$

Velocity Diagram

1. Draw the known vector, cd perpendicular to link CD.

2. Through c, draw a line perpendicular to BC. Point b lies on this line.

3. Draw a line perpendicular to AB from d,(a) to meet the line through c. This is point b.

Bo. 2 0.2 c E 0.4m Znads А 300 D bin Scale kme olm/s shut qol 2391 Vba ale58m/s Yeaal04m Ved zoogels d, a

Velocity of point C = 0.8m/s towards left.

Angular velocity of link BC,

$\omega _{BC}=\frac{V_{bc}}{lengthBC}=\frac{1.37}{0.4}=3.425rad/s$

Velocity of point B $=V_{ba}=V_{bd}=1.58m/s$

Point e is located by the ratio, $\frac{be}{bc}=\frac{BE}{BC}$

Velocity of point E $=V_{ae}=V_{de}=1.04m/s$

Length of AB from geometry = 0.75m

Angular velocity of link AB,

$\omega _{AB}=\frac{V_{ab}}{lengthAB}=\frac{1.58}{0.75}=2.1rad/s$