Question 1

pin at A  is removed and the pole rests on a rough surface at A in the position shown in the figure below. The minimum coefficient of friction at A required for equilibrium is: 
A) 0.41
B) 0.25
C) 0.37
D) 0.64

Accepted Answer

For the pole to be in equilibrium, the net force and torque acting on it should be zero.
Taking moments about point A,
$0.3 \cdot 20 - W \cdot 0.4 \sin(30°) = 0$
$W = \frac{0.6 \cdot 9.8}{\sin(30°)} = 35.29	ext{ N}$
The force acting at A due to the weight of the pole and the load is $W \cdot 0.4 \cos(30°) = 30.59	ext{ N}$
The horizontal force required to balance the pole is $F_h = 30.59	ext{ N}$
The minimum coefficient of static friction required for equilibrium is $\mu_s = \frac{F_v}{F_h} = \frac{W \sin(30°)}{F_h}$
Substituting the values, we get $\mu_s \approx 0.41$
Therefore, the answer is A) 0.41.

Question 2

cable and frictionless pulley system at D is used to bring a 230-kg pole (ACB) to a vertical position as shown in the figure. The cable has tensile force T and is attached at C. The reaction force components, $A _ { x }$ and $A _ { y }$ , at A (in newtons) are: 
A) 3102, 21270
B) 21270, 3102
C) 21342, 4214
D) 23102, 4204

Accepted Answer

B

Question 3

$\text { A painter of weight } W \text { climbs a ladder of weight } W / 3 \text { and length } L . \text { At the position shown in the figure, the }$ $\text { ladder begins to slip. Assume that there is a frictionless roller at } A \text {. What is the coefficient of static friction, } \mu _ { s } \text {, at } B \text { ? }$
 
A) 0.19
B) 0.33
C) 0.68
D) 0.24

Accepted Answer

D

Question 4

reaction force at C (lb) for the beam below is: 
A) 675 lb
B) 985 lb
C) 775 lb
D) 525 lb

Accepted Answer

The answer of reaction force at C (lb) for the...

Question 5

cylinders are in contact along an inclined plane. The upper cylinder (weight is 2.5W) rests against the lower cylinder (weight $W$ ), and both are supported by a wall where the contact force is $N _ { 1 }$. Assume that all friction forces are negligible. An expression for contact force $N _ { 1 }$ in terms of load variable $W$ is: 
A) 1.75W
B) 3.5W
C) 1.57W
D) 2.01W

Accepted Answer

The answer of cylinders are in contact along an inclined...

Question 6

$\text { A cylinder of weight } W _ { 1 } = 150 \mathrm { lb } \text { is supported at two points, } 1 \text { and } 2 \text {, as shown. Neglect friction at the two }$ $\text { points of contact. Normal forces } N _ { 1 } \text { and } N _ { 2 } \text { are (in lb): }$
A) 75, 130
B) 130, 75
C) 125, 150
D) 75, 120

Accepted Answer

The answer of \(\text { A cylinder of weight }...

Question 7

coefficient of friction between a block and the plane is 0.25 (see figure). The minimum horizontal force F (in newtons) required to cause the block to slide up the plane is: 
A) 827
B) 714
C) 609
D) 522

Accepted Answer

The answer of coefficient of friction between a block and...

Question 8

y-direction force on frame ABCDEF below acts at the center of the bar segment to which it is applied. Support B is restrained against translation in the $y \text { and } z$ directions only, and support C is restrained in the $z$ direc-
Tion only. Support D is a pin support. Equilibrium of the frame requires that reaction force $C _ { z }$ is (in newtons): 
A) 80.8 N
B) 67.7 N
C) 14.8 N
D) 92.2 N

Accepted Answer

The answer of y-direction force on frame ABCDEF below acts...

Question 9

Force F required to hold the 75-lb weight in equilibrium is: 
A) 37.50 lb
B) 18.75 lb
C) 56.25 lb
D) 25.0 lb

Accepted Answer

The answer of Force F required to hold the 75-lb...

Question 10

contact force F between the two cylinders in image may be expressed in terms of load variable W as:

A) 1.82W
B) 2.5W
C) 2.1W
D) 1.52W

Accepted Answer

The answer of contact force F between the two cylinders...

Question 11

An adjustable bracket with a collar slides on a pole and is held in place by friction at A and B. The min- imum coefficient of static friction between the pole and collar so that the collar is self-locking against the pole Under applied load F is: 
A) 0.25
B) 0.31
C) 0.42
D) 0.83

Accepted Answer

The answer of An adjustable bracket with a collar slides...

Quiz 3: Equilibrium of Particles and Rigid Bodies: 2D, 3D

pin at A is removed and the pole rests on a rough surface at A in the position shown in the figure below. The minimum coefficient of friction at A required for equilibrium is:

reaction force at C (lb) for the beam below is:

coefficient of friction between a block and the plane is 0.25 (see figure) . The minimum horizontal force F (in newtons) required to cause the block to slide up the plane is:

Force F required to hold the 75-lb weight in equilibrium is:

contact force F between the two cylinders in image may be expressed in terms of load variable W as:

An adjustable bracket with a collar slides on a pole and is held in place by friction at A and B. The min- imum coefficient of static friction between the pole and collar so that the collar is self-locking against the pole Under applied load F is:

Quiz 3: Equilibrium of Particles and Rigid Bodies: 2D, 3D

pin at A is removed and the pole rests on a rough surface at A in the position shown in the figure below. The minimum coefficient of friction at A required for equilibrium is:

cable and frictionless pulley system at D is used to bring a 230-kg pole (ACB) to a vertical position as shown in the figure. The cable has tensile force T and is attached at C. The reaction force components, AxA _ { x }Ax​ and AyA _ { y }Ay​ , at A (in newtons) are:

reaction force at C (lb) for the beam below is:

coefficient of friction between a block and the plane is 0.25 (see figure) . The minimum horizontal force F (in newtons) required to cause the block to slide up the plane is:

Force F required to hold the 75-lb weight in equilibrium is:

contact force F between the two cylinders in image may be expressed in terms of load variable W as:

An adjustable bracket with a collar slides on a pole and is held in place by friction at A and B. The min- imum coefficient of static friction between the pole and collar so that the collar is self-locking against the pole Under applied load F is: