mechanical engineering
EET292 Introduction to Mechanics
Midterm Exam
Note : This is a close-book and close-note exam. Calculator and one formula sheet are allowed in the test.
Time : 3 hours Full mark : 100 points
Part 1: 10×2=20 points. Please choose all correct answers (maybe one or more) for each question and write them on the answer sheet.
1. A vector
A. -100 and 100
B.
V
r
-100 and -100C. -57 and 82
D. -82 and 57
E. 82 and 57
2. Draw a free- body diagram of member AC
3. Which of the following it true about the concurrent force systems : _____
A. Forces do not intersect at a common point
B. Forces intersect at a common point
C. Forces are parallel
D. All forces are acting in opposite direction
4. Which of the following statement is correct about 2-dimensional and 3-dimensional equilibrium : ______
A. In two- dimensional, moments are taken about a point
B. There are no moment equations in 2-dimensional equilibrium
C. In a three- dimensional, moments are taken about an axis
D. There are no force equation in 3-demensional equilibrium
5. In determining the centroid, the distribution is depended on: ______
A. Geometry only
B. Geometry and density of material
C. Geometry, density of material and presence of gravity
D. Density of material and presence of gravity
6. In determining the Center of mass, the distribution is depended on: ______
A. Geometry only
B. Geometry and density of material
C. Geometry, density of material and presence of gravity
D. Density of material and presence of gravity
7. In determining center of gravity, the distribution is depended on: ______
A. Geometry only
B. Geometry and density of material
C. Geometry, density of material and presence of gravity
D. Density of material and presence of gravity
8. Which of the following statement is true about the area moments of inertia _____
A. Measures of how an area is distributed about particular axes
B. Depends on the geometry of an area ( size and shape)
C. Depends on the selected axes
D. Depends on forces and materials
9. Which of the following statement is true about the mass moments of inertia _____
A. Measures of how an area is distributed about particular axes
B. Depends on the geometry of an area ( size and shape)
C. Depends on the selected axes
D. Depends on the density of the material
10. Which of the following statement is true about the mass moments of inertia and area moment of inertia_____
A. Mass moment of inertia used to describe the capacity of a cross-section to resist bending
B. Area moment of inertia used to describe the capacity of a cross-section to resist bending
C. Mass moment of inertia is a measure of resistance to rotational acceleration
D. Area moment of inertia is a measure of resistance to rotational acceleration
Part 2: 4×20=80 points. Please write all your solutions on the answer sheet.
11. For the structure shown below, B is a pin connection and A is a roller connection.
A. Draw a free body diagram
B. Build the equilibrium equations
C. Solve the reaction forces at A and B
12. Determine the load in each member of the concurrent system as shown
13. Determine the moment of inertia about the centroidal x- axis of the areas shown
14. The plate below has a mass of 3000 kg/ m3. Determine the mass moment of inertia about the x- axis