Advanced Crash Investigation

Question 1

A percentage of gravity that affects a vehicle’s ability to decelerate or accelerate.

Answer 1

Coefficient of friction

Question 2

A term that denotes the sharpness of a curve, yawning mark or curb line.

Answer 2

Radius

Question 3

A straight line measurement between two points on an arc that cannot be larger than the diameter.

Answer 3

Chord

Question 4

Skid marks that start, stop and start again. Gaps are 8-10 feet.

Answer 4

Gap skid

Question 5

The braking efficiency of a vehicle for front braking only.

Answer 5

60%

Question 6

The normal split for the braking efficiency of a front engine vehicle, between the front and rear brakes.

Answer 6

60/40

Question 7

The perpendicular measurement from the midpoint of a chord to the edge of an arc

Answer 7

Middle ordinate

Question 8

Skid marks that are regularly and repeatedly interrupted by small gaps. Usually 8 - 10 inch gaps. Measure them from beginning to end as a straight skid.

Answer 8

Skip skid

Question 9

A type of energy that is dissipated as a result of the distance an object moves.

Answer 9

Work

Question 10

The correction made to the minimum speed formula to account for percentage of available factor.

Answer 10

Braking efficiency

Question 11

A mark left by a tire that is rotating and sliding sideways

Answer 11

Yaw mark

Question 12

A measurement between the centers of the axles of a vehicle

Answer 12

Wheelbase

Question 13

The system that defines the order math functions must be performed in an equation

Answer 13

Mathematical order of operation

Question 14

Term used to express the amount of rise or fall relationship to the run of the slope.

Answer 14

Grade

Question 15

Determined by the force necessary to maintain constant movement of the object across the surface

Answer 15

Dynamic friction

Question 16

A device used to determine the coefficient of friction of a surface

Answer 16

Drag sled

Question 17

Determined at the moment the force overcomes the inertia of the object and starts to slide across the surface

Answer 17

Static friction

Question 18

When determining the minimum speed from its skid mark, you should average the length of the skid marks

Answer 18

Minimum speed from skid marks

Question 19

When working on a crash across surfaces with multiple drag factors, where do we begin?

Answer 19

Start at the end of the crash

Question 20

When working with a crash across surfaces with multiple drag factors, which speed calculation will provide a true speed?

Answer 20

The speed calculation on the last surface before the vehicle stopped.

Question 21

When working with a crash across surfaces with multiple drag factors, what can calculated speed values for the individual surfaces be useful for?

Answer 21

Kinetic energy calculations

Question 22

A angle of less than 90 degrees

Answer 22

Acute angle

Question 23

A combination of tangible and intangible points

Answer 23

Semi-tangible

Question 24

The relationship between the opposite side and the hypotenuse of a right triangle.

Answer 24

Sine

Question 25

Greater than a 90 degree angle

Answer 25

Obtuse angle

Question 26

An angle of 90 degrees

Answer 26

Right triangle

Question 27

Airborne equation used when an object launches and lands on the same plane.

Answer 27

Flip formula

Question 28

Rate of acceleration due to gravity.

Answer 28

32.2 fps^2

Question 29

Airborne equation used when an object is on a negative grade before launch.

Answer 29

Fall formula

Question 30

A rough pencil sketch that identifies points to be measured at a collision scene

Answer 30

Field sketch

Question 31

A perpendicular measurement from the midpoint of a chord to the edge of an arc.

Answer 31

Middle ordinate

Question 32

Rate of motion expressed as miles per hour

Answer 32

Speed

Question 33

The relationship between the adjacent side and the hypotenuse of a right triangle.

Answer 33

Cosine

Question 34

A system of measurements that requires only one reference point

Answer 34

Coordinate system

Question 35

A useful means of organizing the measurement data taken from a crash scene.

Answer 35

Data block

Question 36

A method of locating a spot at a scene by measurements from two or more reference points

Answer 36

Triangulation method

Question 37

Rate of motion expressed in feet per second

Answer 37

Velocity

Question 38

A point that does not physically exist.

Answer 38

Intangible

Question 39

Occurs when two straight lines meet at a point

Answer 39

Angle

Question 40

A reference point that physically exists

Answer 40

Tangible reference point

Question 41

Rate of change of velocity with respect to time.

Answer 41

Rate of acceleration

Question 42

Which airborne formula is the most accurate?

Answer 42

Vault formula

Question 43

Where is the center of mass for a pedestrian assumed to be?

Answer 43

At one-half the pedestrian’s height.

Question 44

When should the Fall Formula not be used?

Answer 44

When Grade (G) is above 10% or take off angle is less than 6 degrees.

Question 45

What is the one measurement that absolutely must be taken at a scene?

Answer 45

Drag factor

Question 46

For investigative purposes, weight multiplied by the speed of the vehicle.

Answer 46

Momentum

Question 47

Method used to determine speeds of vehicles at impact, based on post-impact speeds and weights.

Answer 47

Conservation of momentum

Question 48

Used to determine braking distance on a skid test

Answer 48

Longest skid

Question 49

Used to determine braking distance on a crash

Answer 49

Average skid

Question 50

Grade above which you should not use the Fall Formula

Answer 50

10%

Question 51

The angle above which you cannot use the Fall Formula

Answer 51

6 degrees

Question 52

What to use for drag factor when the vehicles join as one at impact and less than all eight wheels are locked?

Answer 52

Effective Factor