Wright State University ME 212 Statics, Spring 2006
Department of Mechanical and Materials Engineering
MIDTERM EXAM 2
Open Book, Closed Notes, Do not write on this sheet, Show all work
- (40points)Using the method of sections, determine the forces in members BC, BG, and FG. Make sure to denote whether the members are in tension or in compression.
- (20 points)When the plunger A is pushed between the rollers B by the force P, the gripper can produce a large gripping force Q. The springs C return the fingers to the open position when the plunger is withdrawn. Assuming that the forces in the springs are relatively small, determine the relation between the activating force P and the gripping force Q.
Wright State University ME 212 Statics, Spring 2006
Department of Mechanical and Materials Engineering
MIDTERM EXAM 2
Open Book, Closed Notes, Do not write on this sheet, Show all work
- (20points)The arm of the excavator is controlled by three hydraulic cylinders. If the soil in the scoop weighs 780 lb, with center of gravity at G, find the magnitude of the force applied by the cylinder AB to the arm BC and the reaction at point C.
- (20 points, No partial credit will be awarded) Draw the freebody diagrams for the following situations. Do not solve!
(a)
The blade of the bulldozer is rigidly attached to a linkage consisting of the arm AB, which is controlled by the hydraulic cylinder BC. There is an identical linkage on the other side of the bulldozer. Determine the magnitudes of the pin reactions at A, B, and C. / (b)
For the pliers shown, determine the relationship between the magnitudes of the applied forces P and the gripping forces at E.
(c)
The tensioning mechanism of a magnetic tape drive has a mass of 0.4 kg, and its center of gravity is at G. The tension T in the tape is maintained by presetting the tensile force in the spring at B to 14 N. Calculate T and the pin reaction at A. / (d)
The tongs shown are designed for lifting blocks of ice. If the weight of the iceblock is W, find the horizontal force between the tongs and the iceblock at C and D. Note that there is a pinned connection at B.
Wright State University ME 212 Statics, Spring 2006
Department of Mechanical and Materials Engineering
MIDTERM EXAM 2
Open Book, Closed Notes, Do not write on this sheet, Show all work
Bonus Question: (20 points, No partial credit will be awarded) Determine the location of the centroid of the machine part shown in the y-direction.