PSAD 1 - Part 1

PSAD – 1
CE REVIEW
(2D AND 3D FORCES)
FORCE SYSTEMS
Force System is defined as any arrangement where two
or more forces act on a body or on a group of related
bodies.
1. Concurrent Force Systems – occur when forces
whose lines of action pass through or intersect to a
common point
2. Parallel Force Systems – occur when forces whose
lines of action are parallel.
3. Non-concurrent Force Systems - Forces whose lines
of action neither are parallel nor intersect on a common
point COMPONENTS OF A FORCE IN PLANE:
Principle of Transmissibility - states that the point of EQUILLIBRIUM OF FORCES
application of a force can be moved anywhere along its
Equilibrium is the term to designate the condition where
line of action without changing the external reaction
the resultant force is zero.
forces on a rigid body.
It can be characterized as,
1. Static or at rest
2. ∑F = 0
Parallelogram Law - It states that if two concurrent 3. If dynamic, acceleration is zero.
forces, acting simultaneously on a body be represented
in magnitude and direction by the two sides of a
parallelogram then their resultant may be represented in DIFFERENT TYPES OF SUPPORTS
magnitude and direction by the diagonal of the
parallelogram, drawn from the same point.

Triangle Law - states that when two vectors are
represented as two sides of the triangle with the order of
magnitude and direction, then the third side of the
triangle represents the magnitude and direction of the
resultant vector.
Sample problem (2D Forces)

PSAD – 1
CE REVIEW
(2D AND 3D FORCES)
1. Knowing that the tension in cable BC is 725N, single-shear connection. All pins are 7mm in
determine the resultant of the three forces diameter. Assume a=600mm, b=300mm,
exerted at point B of beam AB. h=450mm, p=900N, and 𝜃 = 55°. Determine
the following:
A. Force and normal stress in rod (1)
B. Reaction at A
C. Shear stress at A and B
2. A bin holds three cylinders, each weighing 1200

N. The diameter of each cylinder is 600 mm.
Assume frictionless surface. 5. A load P is supported by a cable AB and a
spring AC, when p=240 N, the angle 𝜃 = 60°.
Consider k=500 N/m for the spring:
a. If cable AB is 0.60m long, determine the
force in cable AB,
b. Determine the force in spring AC.
c. Find the unstretched length of spring in mm.
a. Determine the force at point A

b. Determine the force at point D
c. Determine the force at point G
3. The hook is subjected to three forces P, Q, and
6. The square plate has a mass of 1800kg. If the
S. If P=35kN and Q=45 kN
plate is to be lifted while remaining horizon.
Determine the force AD, BD, and CD.
a. Determine the angle 𝛼 such that the resultant

of the three forces is 80kN acting
horizontally to the right.
7. The bell-crank mechanism is in equilibrium for
b. If angle 𝛼 = 60, find the magnitude S, in
the forces acting in rods (1) and (2). The bell
kN, such that the resultant force is horizontal
crank is supported by a 10-mm diameter pin at B
to the right
that acts in single shear. Assume a=65mm,
c. Find the magnitude of the forces S such that
b=150mm, F1=1,100N, and 𝜃 = 50°. Determine
the three forces are in equilibrium.
the ff:
4. Rigid bar ABD is supported by a pin at bracket
A. Force at rod (2)
A and by a tie rod (1). Tie rod (1) has a diameter
B. Resultant force at B
of 5mm, and it is supported by double-shear pin
C. Shear stress in pin B
connection at B and D. The pin at bracket A is a
PSAD – 1
CE REVIEW
(2D AND 3D FORCES)
D. Minimum thickness of bell crank if the 3. A balloon is tied up in three cables. The balloon
allowable bearing stress is 18MPa. exerts a 1000 N vertical force and the wind
exerts a 100N force along positive X direction
acting at point A. Determine the force in
Problem for Practice

1. A load P is supported by the tripod. If the force
in any legs is limited to 2000N. member AB, AC, and AD.
a. Determine the force in member AD

b. Determine the force in member AC
c. Determine the force in member AB
d. Determine the maximum load P that can be
supported by the tripod.
2. A transition tower is held by three guy wires
attached to a pin at A and anchored by bolts at
B, C, and D. If the tension in wires AB is 630 lb,
determine the:
a. Force P exerted by the tower on A.
b. The tension in wire AC
c. The tension in wire AD

PSAD 1 - Part 1

Uploaded by

Copyright:

Available Formats

PSAD 1 - Part 1

Uploaded by

Document Information

Original Description:

Copyright

Available Formats

Share this document

Share or Embed Document

Sharing Options

Did you find this document useful?

Is this content inappropriate?

Copyright:

Available Formats

PSAD 1 - Part 1

Uploaded by

Copyright:

Available Formats

PSAD – 1

parallelogram, drawn from the same point.

Sample problem (2D Forces)

2. A bin holds three cylinders, each weighing 1200

a. Determine the force at point A

a. Determine the angle 𝛼 such that the resultant

Problem for Practice

a. Determine the force in member AD

You might also like