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

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:

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:

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

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

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:

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:

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

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):

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

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

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: