MACHINE DESIGN - An
3-22-1
PROBLEM 3-22
Statement: A roller-blade skate is shown in Figure P3-10. The polyurethane wheels are 72 mm dia. The skate-boot-foot combination weighs 2 kg. The effective "spring rate" of the person-skate subsystem is 6000 N/m. Fi
MACHINE DESIGN - An
3-21-1
PROBLEM 3-21
Figure P3-9 shows an automobile wheel with two common styles of lug wrench being used to Statement: tighten the wheel nuts, a single-ended wrench in (a), and a double-ended wrench in (b). In each case two hands are
MACHINE DESIGN - An
3-20-1
PROBLEM 3-20
Assume that the load of paper rolls in Problem 3-18 will slide sideways at a truck speed of 20 Statement: mph on the curve in question. Estimate the impact force of the cargo against the trailer wall. The force-defl
MACHINE DESIGN - An
3-19-1
PROBLEM 3-19
Assume that the CG of the paper rolls in Problem 3-18 is 2.5 ft above the floor of the trailer. Statement: At what speed on the same curve will the pile of rolls tip over (not slide) with respect to the trailer? Giv
MACHINE DESIGN - An
3-18-1
PROBLEM 3-18
A tractor-trailer tipped over while negotiating an on-ramp to the New York Thruway. The Statement: road has a 50-ft radius at that point and tilts 3 deg toward the outside of the curve. The 45-ft-long by 8-ft-wide b
MACHINE DESIGN - An
3-17-1
PROBLEM 3-17
A pair of ice tongs is shown in Figure P3-7. The ice weighs 50 lb and is 10 in wide across the Statement: tongs. The distance between the handles is 4 in, and the mean radius r of a tong is 6 in. Draw free-body diag
MACHINE DESIGN
An Integrated Approach
3-16-1
PROBLEM 3-16
Statement: A track to guide bowling balls is designed with two round rods as shown in Figure P3-6. The rods are not parallel to one another but have a small angle between them. The balls roll on th
MACHINE DESIGN - An
3-15-1
PROBLEM 3-15
A pen plotter imparts a constant acceleration of 2.5 m/sec 2 to the pen assembly, which travels Statement: in a straight line across the paper. The moving pen assembly weighs 0.5 kg. The plotter weighs 5 kg. What co
MACHINE DESIGN - An
3-14-1
PROBLEM 3-14
Figure P3-5 shows a child's toy called a pogo stick. The child stands on the pads, applying Statement: half her weight on each side. She jumps off the ground, holding the pads up against her feet, and bounces along
MACHINE DESIGN - An
3-13-1
PROBLEM 3-13
Determine the impact force and dynamic deflection that will result when a 100-kg person Statement: jumps up 25 cm and lands back on the board. Assume the board weighs 19 kg and deflects 8.5 cm statically when the pe
MACHINE DESIGN - An
3-12-1
PROBLEM 3-12
An overhung diving board is shown in Figure P3-4b. Find the reaction forces and construct Statement: the shear and moment diagrams for this board with a 100 kg person standing at the free end. Determine the maximum
MACHINE DESIGN - An
3-11-1
PROBLEM 3-11
Determine the impact force and dynamic deflection that will result when the 100-kg person Statement: in Problem 3-10 jumps up 250 mm and lands back on the board. Assume that the board weighs 29 kg and deflects 131 m
MACHINE DESIGN - An
3-10-1
PROBLEM 3-10
An overhung diving board is shown in Figure P3-4a. Find the reaction forces and construct Statement: the shear and moment diagrams for this board with a 100 kg person standing at the free end. Determine the maximum
MACHINE DESIGN - An
3-9-1
PROBLEM 3-9
A ViseGrip plier-wrench is drawn to scale in Figure P3-3. Scale the drawing for dimensions. Statement: Find the forces acting on each pin and member of the assembly for an assumed clamping force of P = 4000 N in the p
MACHINE DESIGN - An
15-1-1
PROBLEM 3-8
Statement:
_
A cam-follower system similar to that shown in Figure 3-15 has a mass m = 1 kg, a spring constant k = 1000 N/m, and a damping coefficient d = 19.4 N-s/m. Find the undamped and damped natural frequencies
MACHINE DESIGN - An
3-7-1
PROBLEM 3-7
The piston of an internal-combustion engine is connected to its connecting rod with a "wrist Statement: pin." Find the force on the wrist pin if the 0.5-kg piston has an acceleration of 2 500 g. Units: Given: kN
3 10
MACHINE DESIGN - An
3-6-1
PROBLEM 3-6
For the trailer hitch of Problem 3-4, determine the horizontal force that will result on the Statement: ball from an impact between the ball and the tongue of the 2000-kg trailer if the hitch deflects 2.8 mm dynamical
MACHINE DESIGN - An
3-5-1
PROBLEM 3-5
For the trailer hitch of Problem 3-4, determine the horizontal force that will result on the Statement: ball from accelerating a 2000-kg trailer to 60 m/sec in 20 sec. Units: Given: kN
3 10 .newton
Mass of trailer Fin
MACHINE DESIGN - An
3-4-1
PROBLEM 3-4
The trailer hitch from Figure 1-1 (p. 12) has loads applied as shown in Figure P3-2. The Statement: tongue weight of 100 kg acts downward and the pull force of 4905 N acts horizontally. Using the dimensions of the bal
MACHINE DESIGN - An
3-3-1
PROBLEM 3-3
Draw a free-body diagram of the pedal-arm assembly from a bicycle with the pedal arms in Statement: the horizontal position and dimensions as shown in Figure P3-1. (Consider the two arms, pedals and pivot as one piece
MACHINE DESIGN - An
3-2e-1
PROBLEM 3-2e
Statement: Draw free-body diagrams for the system of Problem 3-1e (pipe wrench). Assumptions: 1. A two-dimensional model is adequate. Solution: See Mathcad file P0302e.
1. A typical pipe wrench with a pipe clamped i
MACHINE DESIGN - An
3-2a-1
PROBLEM 3-2a
Statement: Draw free-body diagrams for the system of Problem 3-1a (bicycle frame). Assumptions: 1. A two-dimensional model is adequate. 2. The lower front-fork bearing at C takes all of the thrust load from the fron
MACHINE DESIGN - An
3-1-1
PROBLEM 3-1
Statement: Which load class from Table 3-1 best suits these systems? (a) Bicycle frame (b) Flag pole (c) Boat oar (d) Diving board (e) Pipe wrench (f) Golf club. See Mathcad file P0301.
Solution:
1. Determine whether
MACHINE DESIGN - An
15-1-1
PROBLEM 2-26
Statement:
_
A part has been designed and its dimensions cannot be changed. To minimize its deflections under the same loading in all directions irrespective of stress levels, which material would you choose from th
MACHINE DESIGN - An
2-25-1
PROBLEM 2-25
Call your local plastic stock-shapes distributors (consult the Yellow Pages) and obtain Statement: current costs per pound for round rod or tubing of consistent size in plexiglass, acetal, nylon 6/6, and PVC. Calcul
MACHINE DESIGN - An
2-24-1
PROBLEM 2-24
Call your local steel and aluminum distributors (consult the Yellow Pages) and obtain Statement: current costs per pound for round stock of consistent size in low-carbon (SAE 1020) steel, SAE 4340 steel, 2024-T4 alu
MACHINE DESIGN - An
15-1-1
PROBLEM 2-23
Statement:
_
Units: Given:
Refer to the tables of material data in Appendix C and calculate the specific stiffness of aluminum, titanium, gray cast iron, ductile iron, bronze, carbon steel, and stainless steel. Rank
MACHINE DESIGN - An
15-1-1
PROBLEM 2-22
Statement:
_
Refer to the tables of material data in Appendix C and determine the strength-to-weight ratios of the following material alloys based on their ultimate tensile strengths: heat-treated 2024 aluminum, SAE
MACHINE DESIGN - An
15-1-1
PROBLEM 2-21
Statement:
_
Refer to the tables of material data in Appendix C and determine the strength-to-weight ratios of the following material alloys based on their tensile yield strengths: heat-treated 2024 aluminum, SAE 10
MACHINE DESIGN - An
2-20-1
PROBLEM 2-20
Statement: look for? Solution: If maximum impact resistance were desired in a part, which material properties would you See Mathcad file P0220.
1. Ductility and a large modulus of toughness (see "Impact Resistance"