homework 23

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EGR 232 Lecture 23 Homework Fall 2013 Chap. 15, Problem 40 Small wheels have been attached to the ends of rod AB and roll freely along the surfaces shown. Knowing that wheel A moves to the left with constant velocity of 1.5 m/s determine a) the angular velocity of the rod b) the velocity of the end B of the rod. Solution: Set up the relative motion equation: i : j: then

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Page 1: Homework 23

EGR 232 Lecture 23 Homework Fall 2013Chap. 15, Problem 40Small wheels have been attached to the ends of rod AB and roll freely along the surfaces shown. Knowing that wheel A moves to the left with constant velocity of 1.5 m/s determine a) the angular velocity of the rod b) the velocity of the end B of the rod.Solution:

Set up the relative motion equation:

i:

j:

then

and

Page 2: Homework 23

EGR 232 Lecture 23 Homework Fall 2013Chap. 15, Problem 43Rod AB moves over a small wheel at C while end A moves to the right with a constant velocity of 500 mm/s. At the instant shown, determine a) the angular velocity of the rod. b) the velocity of end B of the rod.Solution:

Relative motion equation:

Separate out the vector equations:

i:

j:

then

To find the velocity of B:

200

140244.13400

θ θ

Page 3: Homework 23

EGR 232 Lecture 23 Homework Fall 2013Chap. 15, Problem 50Gear A rotates with an angular velocity of 120 rpm clockwise. Knowing that the angular velocity of arm AB is 90 rpm clockwise, determine the corresponding angular velocity of gear B.-----------------------------------------------------Solution:vA=0ωA=120 rpm clockwise = 4π rad/sωAB=90 rpm clockwise = 3π rad/sωB = ?

for rigid body Gear A:

For link AB:

For Gear B:

x

y

D

Page 4: Homework 23

Equating the two equation for velocity of B.

or 70 rpm clockwise.

EGR 232 Lecture 23 Homework Fall 2013Chap. 15, Problem 55Knowing that crank AB has a constant angular velocity of 160 rpm counterclockwise, determine the angular velocity of rod BD and the velocity of collar D when a) θ = 0, b) θ =90 deg

---------------------------------------------------------

Solution:ωAB=160 rpm CCW = 16.76 rad/s-------------------------------------------------for 0 degrees:

For Link AB:

For Link BD:

therefore:

D

Page 5: Homework 23

i: j:

--------------------------------------------------------------------------

For angle of 90 degrees:

For Link AB:

For Link BD:

then:

i: j: