Mec 323 Final

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1- Time- 3 hours

RYERSON UNIVERSITY

Department of Mechanical & Industrial Engineering

MEC323 STATICS AND MECHANICS OF MATERIALS

Final Exam July 2012

2- Answer all questions. All questions have the same value.

3- Appropriate free body diagrams are expected for all problems

4- Closed book examination

5- If you think there is missing or ambiguous information in this exam, make appropriate assumptions, state them clearly, and then solve the problem on the basis of those assumptions.

6- All numerical answers must have appropriate units.

7- Write your answers legibly.

MECU

Obtained from Ryerson's Mechanical Engineering Course Union (MECU)www.ryemecu.com

MECU of 7 www.ryemecu.com

r" Ql Detennine the force in each 1nen1ber of the truss, and state if the 1nembers are in tension or compression. Set P = 4 kN.

...,...__ ·3m .... ... 3m ...

E

I 3m

l MECU



Q2 If a clarnping force of 300 N is required al A~

determine the an1ount of force F that must be applied to the handle of the toggle clamp.

F

?On1m ---235 mm- - ... 1"'"---1

•

MECU



Q3

The tongs are used to lift the 150-kg crate~ whose center of tnass is at c;. Determine the least coefficient of static friction al the pivot blocks so that the crate can be lifted.

p 275 tnm

l 500mm C

500mm

300mm

MECU



Q4

a) Determine the internal resultants FG, V G' and MG on the cross section at G of the horizontal frame member. The uniformly distributed load on member AC has a magnitude ofw0 =220 lb/ft.

b) IfBD has a rectangular cross section measuring 0.50 in. X 2.00 in., what is the axial stress in member BD.

c) The pin at Dis in fact a bolt as shown in Figure b. If the bolt is made of a kind of steel with shear yield strength of 43 ksi and a factor of safety of 3 is required, what . should be the diameter of the bolt. For this calculation you can assume the bolt to · be a smooth pin.

! ......... --3 ft--•J ........ l.5 ft ..... ---1.5 ft .....

4tl

Fig. b

MECU

Obtained from Ryerson's Mechanical Engineering Course Union (MECU) www.ryemecu.com


Qs Steel rods (A = 0.050 in2, E = 30 X 103 ksi, a =

6.5 X 10-6/°F) are attached at points A and C to the ''rigid'' right-angle bracket in Fig.. The bracket is supported by a stnooth pin at B, and the rods at A and C are initially stress-free. (a) Determine the axial stresses induced in rods (1) and (2) if the temperature of rod (1) is decreased by 50°F. {b) Determine the transverse shear force V n and bending moment MD on the cross section at D that result from this temperature change.

... 5 in. ... .. 5 in. •I

I 5 in.

8 in. (1) (2) l +----- 8 in.--_,..

MECU



Q6 The steel shaft AD in Fig. _ ( G = 80 CiPa)

is subjected to torsional loads at sections B and LJ. as shown in the figure. The diameters are: d1 = d2 = 40 n1m . ., and d3 = 30 n1n1. (a) Detern1ine the value of the torque T D added at D that \\'auld n1ake the rotation at G, equal to zero, that is~ make <Pc = 0. (b) For the loading as determined in Part (a).l determine the maximum shear stress in each of the three rod segments.

MECU

Obtained from Ryerson's Mechanical Engineering Course Union (MECU) www.ryemecu.com


Mec 323 Final

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