MMechanics Flashcards
25 ft/s East is an example of what?
Velocity
Every applied force is matched by a force that:
Is opposite in direction and equal in magnitude.
Give an example of thermal expansion:
Road buckling due to freezing water
In the English system, forces are measured in _________
Pounds
A vector is used to designate ______ and ___________
Size and direction
One equation for work?
Force x distance
What is energy?
The ability to do work
How much power is used when lifting a 30lb object a distance of 12 ft in 10 seconds?
Work = 30(12); 360/10= 36ft lb/sec
BTU is a measure of what?
Heat (British thermal unit)
In a machine that is 90% efficient, 10% shows up as what?
Heat (friction)
PSIA stands for:
Pounds per square inch, absolute
Lengthening the tubing in fluid power systems __________ the friction head.
Increases
One important difference between gas and liquids?
Gas can be compressed
The source of pressure exerted on an unconfined liquid is:
Gravity
How do you figure out absolute pressure from gauge pressure?
Add 14.7psi
A cam and follower mechanism changes rotary or linear motion to:
Reciprocating motion
When a simple machine is used to gain speed, it is at the expense of:
Force or effort
Name the 6 simple machines:
Lever, pulley, wedge, wheel and axel, inclined plane, screw.
Which class of lever changes the direction of force?
Class 1 (see-saw)
Actual mechanical advantage is less than ideal because of:
Internal friction
A combo of 2 or more machine parts is called a:
Mechanism
A bell crank has ___ fixed point(s) and ___ movable pivot point(s)
1;2
The input motions of a cam and follower are either:
Rotary or linear
The electric motor is the ________________ of a machine
Prime mover
The most useful type of motion for mixers/cutters is:
Oscillating
Stroboscopic light is often used for:
Rotational speed
Ultrasonic flow meters cannot be used u less the fluid:
Contains bubbles or suspended solids
If an instrument has accuracy of plus or minus 1% and a temp of 500°, what temps could it actually be?
495°-505°
What instrument measures airflow?
Anemometer
The probe of a vibration meter uses ____________ to take measurements.
Electric current
What tool is used to cut heavy-gauge sheet metal?
Bulldog snips
One use for pliers is:
Bending metal
To clamp 2 pieces of metal together for welding, use:
Locking pliers
Another name for a machinists hammer?
Ballpeen hammer
What tool is it okay to strike with a hammer?
Punches
To minimize risk of shock, you should stand on a(n) _____________ platform.
Insulated
You must wear ______ protection when grinding, chipping, hammering.
Eye
Before changing a bit or blade, you must:
Disconnect power
For safety, when using an electric drill, ___________ the chuck key before using
Remove
Prevailing torque nut vs free spinning lock nut?
?
Machine screws are used for:
Light duty applications
The distance from one crest to the next on a screw thread is called the:
Pitch
What type of nut is used when screwing nut and bolt with cotter pin?
Castle
Sliding friction causes:
Wear, energy loss, and heat
What type of friction prevents motion of an object at rest?
Static friction
Name 3 types of kinetic friction:
Sliding, rolling, and fluid
What type of wear leaves blotchy, mottled appearance in metal?
Corrosive wear
