1. Determine the velocity of the block if link 2 if link 10 turns at 10 rad/sec clockwise. Locate all
centros.
(INSERT FIG.)
Example: RELATIVE VELOCITY METHOD
Determine the velocity of block 6 and 3 if link 2 rotates at 10 rad/sec clockwise. πΎπ =
1
4
π ππ§π, πΎπ£ = 40
ππ
π ππ
.
(INSERT FIG.)
(INSERT FIG.)
Velocity Polygon
ππ΄ = 2π2 π΄
= 10(8)
ππ΄ = 80 ππ/π ππ
Procedure:
1) Locate a convenient location for pole c and lay out ππ2 equal and parallel to ππ΄ on 2.
2) To find ππ΄ on 4, ππ΄ on 4 = ππ΄ on 2. Sliding velocity
(a) Lay our from π2 a line parallel to link 4 representing the sliding velocity of the block.
(b) From pole c, draw a line parallel to the direction line of the velocity of A on 4 which
is perpendicular to link 4. ππ΄ ππ 4 = ππ4 π₯ πΎπ£ = 1.35(40) = 54 ππ/π ππ
3) To find ππ΅ ,
Points A on 4 and 3 are rotating about the same axis of rotation, the velocities
are proportional to its distances from π4, likewise, the length of the vector in the
velocity polygon is proportional to its distance from pole c. Therefore,
4) To find ππ· , ππ· = ππ΅ ; ππ΅π·
a) Lay out a line from pole a parallel to the direction line of the velocity of the block.
b) Draw a line perpendicular to BD which is the direction line of the velocity of B
relative to D.
c) Measure cd, ππ· = ππ π₯ πΎπ£ = 0.58(40) = 20 ππ/π ππ
=
π π΅ π·
π΅π·
=
0.35(40)
28
= 0.50 πππ/π ππ
Example: RELATIVE VELOCITY METHOD
Determine the velocity of point B and the point of contact between the two
gears if the angular velocity of crank 2 is 10 rad/sec and gear 5 roll on gear 3 π₯ π£ = 10 ππ/π ππ
2. (INSERT FIG.)
Direction line of Point 0 on 3 rotating about π2.
ππ΄ = π2 π π₯ π2
ππ΄ = 10(2)
ππ΄ = 20 ππ/π ππ.
(INSERT FIG.)
Velocity Polygon
ππ΄ = ππ΅ ππ΅π΄
ππ΅ = ππ π₯ πΎπ£
ππ΅ = 1.6(10)
ππ΅ = 16 ππ/π ππ.
π0 ππ 3 = π0 ππ 5 = ππ΄
= 4(10) = 40 ππ/π ππ
Oa is equal and parallel to ππ΄
hao perpendicular to AB.
Cb perpendicular to π4 π
Co perpendicular to π2 π
If crank 2 rotates uniformly at 20 rad/sec, determine the velocity of block 6 and the angular
velocity of link 5 in rad/sec. πΎπ = 4ππ/ππ.
(INSERT FIG.)
Crank 2 rotates counterclockwise with an angular speed of 30 rad/sec. Determine
ππ΅, ππ·, ππΈ, π3 , π4 πππ π7. πΎπ = 3 ππ/ππ.
(INSERT FIG.)
Determine the velocity of block 5 and 4 if crank 2 rotates at 10 rad/sec. πΎπ = 2ππ/ππ.
(INSERT FiG.)