Topic 1: Statics

Question 1

Crow bar

Answer 1

First-class lever, iron/steel bar used to wedge under an object to move or lift it

Question 2

Bicycle

Answer 2

simple machine made of several components: axial, spoke, gear chain, crankshaft, pedals, vehicle used for transportation

Question 3

Car jack

Answer 3

simple machine used as a lifting device

Question 4

Linear motion

Answer 4

motion in a straight line

Question 5

Rotary motion

Answer 5

motion in a circular path, motion about an axis

Question 6

Oscillatory motion

Answer 6

motion that an object repeats continuously

Question 7

Reciprocal motion

Answer 7

repetitive back-and-forth linear motion

Question 8

Mechanical Advantage

Answer 8

MA=load/effort

Question 9

Velocity Ratio

Answer 9

VR=distance moved by effort/distance moved by load

Question 10

Efficiency

Answer 10

efficiency= MA/VR x100%

Question 11

First class lever

Answer 11

Load-Fulcrum-Effort

Question 12

Second class lever

Answer 12

Fulcrum-Load-Effort

Question 13

Third class lever

Answer 13

Load-Effort-Fulcrum

Question 14

Mechanical Advantage of Levers

Answer 14

MA=Load/Effort=distance to effort/distance to load

Question 15

Velocity Ratio of Levers

Answer 15

VR=distance to effort/distance to load

Question 16

Reducing Gears

Answer 16

the driver gear is smaller than the driven gear. Acts as a force multiplier but reduces speed

Question 17

Multiplying Gears

Answer 17

the driver gear is bigger than the driven gear. Acts as a speed multiplier

Question 18

Velocity ratio of Gears

Answer 18

VR=rpm of driver/ rpm of driven

Question 19

Gear ratio of Gears

Answer 19

GR=driven/driver

Question 20

Mechanical advantage of Gears

Answer 20

MA=GR

Question 21

Efficiency of Gears

Answer 21

MA/VR or GR/VR

Question 22

Velocity Ratio of Worm drives

Answer 22

VR=number of teeth on worm gear/threads on worm

Question 23

Gear ratio of Rack and pinion

Answer 23

GR= pinion teeth/rack pitch

Question 24

Mechanical Advantage of Inclined Planes

Answer 24

MA= load/effort

Question 25

Velocity Ratio of Inclined Planes

Answer 25

VR=distance moved by effort (along plane)/distance moved by load (vertically up) = 1/sinx

Question 26

Mechanical Advantage of Screws

Answer 26

MA= load/effort

Question 27

Velocity ratio of Screws

Answer 27

VR= distance moved by effort/ distance mover by load= circumference/pitch

Question 28

Pulleys

Answer 28

used to transmit power, change direction of force, provide assistance using MA

Question 29

Velocity Ratio of First-order pulley system

Answer 29

VR=2^p, p=movable pulleys in system

Question 30

Velocity Ratio of Second-order pulley system

Answer 30

VR=n, n= number of rops supporting lower pulleys

Question 31

Mechanical Advantage of pulleys

Answer 31

efficiency x n or efficiency x 2^p

Question 32

Work

Answer 32

W=Fd=Fdcosx=area under a force-displacement graph

Question 33

Power

Answer 33

P=W/t=E/t=Fd/t

Question 34

Potential Energy

Answer 34

PE=mgh

Question 35

Kinetic Energy

Answer 35

KE=1/2*mv^2

Question 36

Energy Efficiency

Answer 36

efficiency= useful output/input

Question 37

Linear Motion

Answer 37

v=u+ at, v^2=u^2+as, s=ut+1/2*at^2, average velocity=s/t

Question 38

Friction

Answer 38

force that opposes the motion of an object

Question 39

Static Friction Force

Answer 39

force that keeps object at rest/just at the point of moving, F=coefficient of static friction x normal force

Question 40

Kinetic Friction Force

Answer 40

force when there is relative motion.
F=coefficient of kinetic friction x normal force

Question 41

coefficient of friction

Answer 41

coefficient of friction= friction force/normal force = tanx

Question 42

limiting friction

Answer 42

frictional resistance that exists just as motion is about to occur

Question 43

Angle of static friction (phi)

Answer 43

angle between resultant reaction and normal reaction

Question 44

Angle of repose (theta)

Answer 44

angle of the inclined plane