MEEM 3400
Week 5 HW
Spring 2024
NAME: _____________________________________________
Answer the following questions, showing your work for full credit. Upload as a single PDF to the assignment in
Canvas, by the deadline posted. No late homework accepted, unless prior permission is provided.
Problem 1:
If ω2 = 5 rad/s CCW in Figure below, find ω5 using instant centers.
I34
135
145
I 12
115
I 25
I23
I 13
Hint: Find I12, I15 and then I25.
WE
5rads
4.3750dg
MEEM 3400
Week 5 HW
Spring 2024
NAME: _____________________________________________
Problem 2:
Crank 2 of is driven at ω2 = 60 rad/s (CW). Find the velocity of points B and C and the angular velocity of links 3 and 4
using the instant-center method. The dimensions are in centimeters.
Hint: work on the scaled chart (printed) and use a known dimension (say 15.05 cm) as a scale to obtain dimensions in
need.
134
S
40rad
In
I23
W z 60radso
Irs
I
43.7rad's
VB 43 7rad's 13.1 572.3
437rads 5.7 2494
2
MEEM 3400
Week 5 HW
Spring 2024
NAME: _____________________________________________
Problem 3:
If ω2 = 1 rad/s CCW, find the velocity of point D on link 6 using the Instant Center Method. Show vD6 on the drawing. The
units are in inches.
113
I 12
136 up
126
113
3
5
125
4
116
Ily
iii
6
3
5
123
4
Wo tradls
2rads
2rad's
1.4in
2
2.81ns
MEEM 3400
Week 5 HW
Spring 2024
NAME: _____________________________________________
Problem 4:
As
Design a double-rocker, four-bar linkage so that the base link is 4 in and the output rocker is 2 in long. The input link
turns counterclockwise 40° when the output link turns counterclockwise through 80°. The initial angle for the input link
is 20° counterclockwise from the horizontal, and the initial angle for the output link is 25°. The geometry is indicated
below.
A
MEEM 3400
Week 5 HW
Spring 2024
NAME: _____________________________________________
Problem 5:
Design a double-rocker, four-bar linkage so that the base link is 2 in and the output rocker is 1 in long. The input link
turns counterclockwise 60° when the output link turns clockwise through 90°. The initial angle for the input link is 30°
counterclockwise from the horizontal, and the initial angle for the output link is -45°. The geometry is indicated below.
MEEM 3400
Week 5 HW
Spring 2024
NAME: _____________________________________________
Problem 6:
A four-bar linkage is often used to retract the saw guard
on a cutoff saw as the saw is moved into a piece of wood.
A typical saw is shown in its lowest position in the figure.
If r2 rotates 47 degrees when r4 rotates 52 degrees, design
an appropriate linkage to rotate the blade guard. Use the
sketch below as your starting point, which represents the
four-bar linkage for retracting the saw guard. Assume that
r1 is 2” and r4 is 9 ½”. What is the total rotation of link 3
relative to the frame for your design?
72 1270