MECHANICAL REASONING
A) A (figure one the far right, not labeled correctly is study guide) Pressure is define as Force/Area. For a given force, 20lbs, the smaller the area, the greater the pressure produced. The smallest area is as position A, requiring the least force to lift the weight.
Which hydraulic press requires the least force to lift the weight? A) A B) B C) C D) All three require the same force
B) If the head of the bolt is held stationary and the nut is turned clockwise the nut will move down. Clockwise is right to left, so if the nut moves, it follows the threads of the bolt downward.
Which of the following statements is true about the figure above? A) If the nut is held stationary and the head turned clockwise the bolt will move up. B) If the head of the bolt is held stationary and the nut is turned clockwise the nut will move down. C) If the head of the bolt is stationary and the nut is turned clockwise the nut will move up. D) If the nut is held stationary and the bolt it turned counterclockwise the nut will move up
A) Insulating the pipe Insulating the pipes keeps warm moisture-laden air from coming into contact with the cold pipes. This stops condensation.
Condensation on cold water pipes is frequently prevented by A) Insulating the pipe B) Keeping the temperature of cold water at least 10° above the freezing point C) Keeping the cold water lines near the hot water lines D) Oiling or greasing the outside of the pipe
B)Metal Spoon Metal will feel coldest out of paper, wood, and the fabric of a blanket.
If all of the following objects are at room temperature, which will feel coldest? A) Book B) Metal Spoon C) Wooden Chest D) Blanket
A)A Pulley A is the smallest gear. Therefore, it must turn faster (make more revolutions per minute).
In this arrangement of pulleys, which pulley turns fastest? A) A B) B C) C D) D
A) C toward the right If nut A were removed, it would be necessary to move nut C to the right to counterbalance the loss of the weight of nut A.
1. The arm in the figure above is exactly balanced as shown. If nut A is removed entirely, then, in order to rebalance the arm, it will be necessary to turn nut A) C toward the right B) C toward the left C) B up D) B down
B) Bend the strips The figure shown is a bimetallic strip that works like the wire in a thermostat. High temperatures will cause the metals to heat unevenly. The rivets will keep the strips together, so the only thing that they can do is bend.
1. The figure above shows a brass and an iron strip continuously riveted together. High temperatures would probably A) Have no effect at all B) Bend the strips C) Separate the strips D) Shorten the strips
A) 1/4 turn Each time the rotating arm makes a complete revolution, it moves the slotted disc 1/4th of a turn.
1. The figure above shows a slotted disc turned by a pin on a rotating arm. One revolution of the arm turns the disc A) 1/4 turn B) 1/2 turn C) 3/4 turn D) 1 complete turn
A)21 Since gear A has 15 teeth and gear B has 10 teeth, gear A is 1.5 the size of gear B. Therefore, 14 x 1.5 = 21.
1. When gear A makes 14 revolutions, how many revolutions will gear B make? A) 21 B) 17 C) 14 D) 9
A)Once The single lobe on cam A will cause the setscrew to hit the contact point once during the cam's revolution.
As cam A makes one complete turn in the figure above, the setscrew will hit the contact point A) Once B) Twice C) Three Times D) Not At All
B) Float When the water level rises past the safe area, the float turns on the sump pump. When the lever of water in the sump pump goes down, the float also goes down and will shut off the sump pump. Extra Note: Sump pumps are devices that are placed in a basement designed to pump out excess water that would otherwise cause significant flooding. They are almost always put in the lowest point in the floor and often placed in their own specially dug pit.
Automatic operation of a sump pump is controlled by the A) Pneumatic Switch B) Float C) Foot Valve D) Centrifugal Driving Unit
B)32 gallons per minute The volume is dependent on the area of the outlet. Since A= πr² and r = d/2 , then A= π(d²/4) where A is the area and d is the diameter. The volume is proportional to the diameter squared (d²). When the volumes of the 1-inch and 2-inch outlets are compared, we see that the latter will produce 4 times as great a volume. If the 1-inch outlet has an 8-gallon flow, then the 2-inch outlet will have a 32-gallon flow.
Eight gallons of water per minute are flowing at a given time from the 1-inch outlet in the tank shown above. What is the amount of water flowing at that time from the 2-inch outlet? A) 64 gallons per minute B) 32 gallons per minute C) 16 gallons per minute D) 2 gallons per minute
C) 12 The trick with this question is that both of the rods will be pulled in at the same time when the turnbuckle is turned. If it is turned 12 times (12 threads per inch), both rods will be pulled in 1 inch.
For the turnbuckle shown above, the number of complete turns of Part 1 required to make the ends of the threaded rods meet is A) 6 B) 18 C) 12 D) 24
D) 1, 3, and 4 To move the pistons to the right, valves 1, 3, and 4 must be open. Valve 4 permits the air to enter the system; valve 3 allows the air to hit the left side of the piston; and valve 1 is an exhaust channel for air.
If all valves are closed at the start, in order to have air pressure from the tank move the pistons to the right, the valves to be opened are A) 2 and 4 B) 2, 3, and 4 C) 1 and 2 D) 1, 3, and 4
D) Waterlogged float The water shut-off valve on a flush tank is closed by force of a lightweight ball rising inside the tank. If the float becomes waterlogged, it will not rise and shut off the water.
If the flush tank of a toilet fixture overflows, the fault is likely to be A) Failure of the ball to seat properly B) Excessive water pressure C) Defective trap in the toilet bowl D) Waterlogged float
A) Rise 1 gallon per minute The water is filling up in the tank at a rate of 120 gallons per hour, or 2 gallons per minute (120/60=2). The tank is also emptying at a rate of 1 gallon per minute. The net flow is increasing at 1 gallon per minute, because 2gal minus 1gal= 1 gallon per minute increase.
If water is flowing into the tank shown above at the rate of 120 gallons per hour and flowing out of the tank at a constant rate of 1 gallon per minute, the water level in the tank will A) Rise 1 gallon per minute B) Rise 2 gallons per minute C) Fall 2 gallons per minute D) Fall 1 gallon per minute
B) 45° There are 8 holes in the circular cross-section of the flanged pipe. A;; circles have 360°. Thus each hole is separated by 360°/8 or 45°
In the case of the standard flanged pipe shown above, the maximum angle through which it would be necessary to rotate the pipe in order to line up the holes is A) 22.5° B) 45° C) 30° D) 60°
B) 175 pounds The diameter of 3½ times (28/8) the diameter of the axel. When 50lbs of force is applied to the handle, it is multiplied by 3½ times, or 28/8x50=175lbs
In the diagram above, the axle 8 inches in diameter has attached a handle of 28 inches in diameter. If the force of 50 pounds is applied to the handle, the axle will lift a weight of A) 224 pounds B) 175 pounds C) 200 pounds D) 88 pounds
A) Study the diagram and not that the follower is at its highest position between points Q and R.
In the figure above, the follower is at its highest position between points A) Q and R B) R and S C) S and T D) T and Q
B) Rise in the air If the man moves to the back of the seesaw, his momentum (weight x distance from the center) will increase. The woman, who is lighter will rise in the air.
In the illustration above, if the man backs to the end of the seesaw, the women will A) Remain stationary B) Rise in the air C) Hit the ground hard D) Slide to her end of the seesaw
C)Air pressure on top of the liquid The siphon works, in part, because of air pressure on the top of the liquid.
In the illustration above, liquid is being transferred from the barrel to the bucket by A) The vacuum at the lower end of the hose B) The difference between the fluid volumes in the barrel and bucket C) Air pressure on top of the liquid D) Capillary action
C) If the head of the bolt is stationary and the nut is turned clockwise, the nut will move up. To tighten the bolt, turn it counter-clockwise. To tighten the nut on the bolt the reverse is true, turn it clockwise.
Referring to the figure above, which one of the following statements is true? A) If the nut is held stationary and the head is turned clockwise, the bolt will move down. B) If the head of the bolt is held stationary and the nut is turned clockwise, the nut will move down. C) If the head of the bolt is stationary and the nut is turned clockwise, the nut will move up. D) If the nut is held stationary and the head turned counter-clockwise, the bolt will move up.
C)C) No. 3 Figure No. 3 has the largest surface area and thus would need the shortest sides. Area is length x width. For No. 3 area= 7ft x 4ft= 28sqft
Shown above are the bottoms of four bins for storing materials. If the bins are all capable of holding the same amount of any particular material, then the bin whose sides have the least height is the one whose bottom is shown as A) No. 1 B) No. 2 C) No. 3 D) No. 4
D) It will take more time for a tooth of wheel P to make a full turn than it will for a tooth of wheel M. Wheel P has 16 teeth. Wheel M has 12 teeth. When wheel M makes a full turn, wheel P will still have 4 more teeth to turn. So wheel P is slower and will take more time to turn.
Study the gear wheels in the figure above, then determine which of the following statements is true. A) If you turn wheel M clockwise by means of the handle, wheel P will also turn clockwise. B) It will take the same time for a tooth of wheel P to make a full turn as it will for a tooth of wheel M. C) It will take less time for a tooth of wheel P to make a full turn than it will take a tooth of wheel M. D) It will take more time for a tooth of wheel P to make a full turn than it will for a tooth of wheel M.
C)Move downward until it reaches the floor Newton's Law of Motion states that a body at rest will stay at rest unless acted on by an outside force. Conversely, a body in motion stays in motion unless acted on by an outside force. In this picture, both objects are at rest (equilibrium). When an outside force is added to weight 1, the equilibrium changes, moving this weight downward. Because the pulley has practically no friction, the weight strikes the floor.
The figure above represents a pulley, with practically no friction, from which two 10pound weights are suspended as indicated. If a downward force is applied to weight 1, it is most likely that weight 1 will A) Come to rest at the present level of weight 2 B) Move downward until it reaches with weight 2 C) Move downward until it reaches the floor D) Pass weight 2 in its downward motion and then return to its present position
A) Y The distortion of the cam causes the valve to rise when contact is made. The amount of this distortion is the length Y.
The figure above shows a cam and a valve. For each cam revolution, the vertical valve rose equals distance A) Y B) X C) X plus Y D) Twice X
B) 3/4 turn The piston is now in part of the compression stroke; 1/4 turn will move it to full compression; 1/2 more turn will move it to the end of the power stroke. Adding 1/4 + 1/2 = 3/4 turn.
The figure above shows a crank and piston. The piston moves from midposition to the extreme right if the crank makes A) 1/2 turn B) 3/4 turn C) 1 turn D) 1 1/2 turns
C) Upward The centrifugal force acts to pull the balls outward. Since the two balls are connected to a yolk around the center bar, this outward motion pulls the balls upward.
The figure above shows a governor on a rotating shaft. As the shaft speeds up, the governor balls will move A) Down B) Upward and Inward C) Upward D) Inward
C) 10 The sum of the moments must be zero. Summing around the fulcrum we have: (6ft x 5lbs) + (3ft x 10lbs) = 6ft x F Combining terms, we get: 60(ft-lbs)=6ft x F Dividing both sides by 6: 10lbs=F
The force F needed to balance the lever shown above is, in pounds, most nearly A) 7.5 B) 12.5 C) 10 D) 15
A) Provide for changes in length of heated pipe When steam flows through pipes, it expands. The pipes would burst if extra space were not provided for the expansion and contraction.
The main purpose of expansion joints in steam lines is A) Provide for changes in length of heated pipe B) Allow for connection of additional radiators C) Provide locations for valves D) Reduce breakage of pipe due to minor movement of the building frame
A) .2270 The measurements that can be made on the micrometer are: A) 2 minor divisions and 1 minor division on the ruler type scale, or .2+.025= .225; B) 2 minor divisions above 0 on the rotating scale, or .002. Summing, we find the final measurement is .225+.002= .227
The micrometer above reads A) .2270 B) .2120 C) .2252 D) .2020
C) Be enlarged The film of water inside the loop would form a lens that would enlarge the printing on the page. If you look through a water filled globe, objects will also appear larger.
The print in the figure above looked at through the film of water will A) Be too blurred to read B) Look the same as surrounding print C) Be enlarged D) Appear smaller
B) Relieve the air from steam radiators. An air valve on a radiator removes air from the steam pipes. If air is trapped in the pipes, it prevents the steam from going to the radiator. This would prevent the radiator from producing heat.
The purpose of an air valve in a heating system is to A) Prevent pressure from building up in a room due to the heated air. B) Relieve the air from steam radiators. C) Allow excessive steam pressure in the boiler to escape to the atmosphere. D) Control the temperature in the room.
D) Find the height of water in the boiler The try-cocks show the lever of the water inside the boiler. They use the principle that water seeks its own level in a system.
The try-cocks of steam boilers are used to A) Act as safety valves B) Empty the boiler of water C) Test steam pressure in the boiler D) Find the height of water in the boiler
B) 36 pounds Let Y= effort that must be exerted Step1 60x3=Yx5 Step2 180=5Y Step3 Y=180/5 Step4 Y=36
What effort must be exerted to lift a 60 pound weight in the figure of the first class lever shown above(disregard the weight of the lever in your computation)? A) 30 pounds B) 36 pounds C) 45 pounds D) 60 pounds
D) Upper Block Because the upper block is connected to an immovable hook, it must remain stationary.
When load is hoisted by means of the tackle shown above, the part that remains stationary is the A) Load B) Lower Block C) Lower Hook D) Upper Block
C) 150 pounds The downward pull equals the 100-1b. weight being hoisted plus the 50-1b. effort required with the single movable block in the pulley, which has a mechanical advantage of 2. 100 lbs. + 50 lbs. = 150 lbs.
When the 100-pound weight is being slowly hoisted up by the pulley, as shown in the figure above, the downward pull on the ceiling to which the pulley is attached is A) 50 pounds B) 100 pounds C) 150 pounds D) 200 pounds
B) Turn Slower Imagine the driven wheel as a record. For one rotation of the record, point Y travels much farther than point X. It takes more more turns of the driver wheel to turn point Y one complete revolution.
When the driver wheel in the figure above is moved location X to location Y, the driven wheel will A) Reverse its direction of rotation B) Turn Slower C) Not change its speed of rotation D) Turn faster
D) Swing away from the tuning fork When the tuning fork vibrates it moves currents of air. This vibrating air would cause the ping pong ball to be pushed away.
When the tuning fork shown above is struck the ping pong ball will A) Remain Stationary B) Bounce up and down C) Hit the tuning fork D) Swing away from the tuning fork
C)Neither of the other gears Because of the way the gears are meshed, both gear 1 and gear 3 will move in the opposite direction of gear 2.
Which of the other gears is moving in the same direction as gear 2? A) Gear 1 B) Gear 3 C) Neither of the other gears D) Both of the other gears
A)Post A The weight is distributed more on the side of post A, Therefore, it is holding up the greatest part of the load.
Which post holds up the greater part of the load? A- Post A B- Post B C- Both equal D- Not clear
A) Pulley A The mechanical advantage is calculated by the number of strands supporting the weight. A has 3 strands, B has 2, C only has 1
Which pulley arrangement shown above requires the least force at F to lift the weight? A) A B) B C) C D) All 3 require the same force
