The Demon!
Type of Ride:
Roller Coaster, Gravity driven


Key Terms:

Acceleration, Friction, Force, Inertia, Kinetic Energy, Mass, Momentum, Potential Energy, Velocity.

Useful Formulas:

For similar triangles: h1 / h2 = l1 / l2

For triangulation: h1 = L tan q

Total height = h1 + h2

For Speed: S = d / t


88 ft/s = 60 mph; 1 ft/s 1 mph; 1 m/s 2mph

1 ft/s = 0.30 m/s; 1 mph = 1.60 km/hr


Length of track = 2,300 ft. or 700 m

Height of first hill = 100 ft or 30.3 m

Preparation / Pre Lab
Measuring Heights


meter/yard sticks, protractors, thread, small fishing weights, data books, and chalk.

1. Using Similar Triangles:

* Review proportions with students

* Have students record each other’s heights .

* Students should then find the average of one walking pace. (walk along a meter/yard stick )

* Record both personal height & pace in lab book.

* Measuring shadows on a sunny day. (Partners should record each others’ shadow , then measure or pace off the shadow of a distant object cast on the playground, ie: flagpole, building, or telephone pole.)

* Bring data back into the class room to do calculations.

*Compare answers, if possible obtain exact height of pole to compare with students’ measures. 

2.Using Triangulation:

* Prepare protractor for measuring < s by stringing a fishing line through the vertex hole in protractor bring line together using a pinch fishing weight.

* The straight edge of the protractor will be used as a sight line; the angle measure is read by the partner eyeing the plumb line.(see worksheet).

* Review with students how to determine the tangent of an angle.

* Student partners should record each other’s height from the eye level to ground (h1)

* Return to the outdoors. Students should take a position a measurable distance from the flagpole, telephone pole etc..

* Protractors should be used to measure angle to top of pole from a standing position facing the pole. The angle measure is recorded by the partner.

* Pace off or measure the distance from the flagpole.

* Fit data into formula and solve for h .

Calculating Speed:


Stopwatch, skateboard/coaster or similar, and lab book.


3. Measuring Speed
* Measure out the distance of your chosen ramp or hill, a trundle wheel is helpful in measuring the course.

* Student at top of ramp roll down ramp / hill at signal of timer.

* Timers record duration of ride.

* Repeated trials are necessary to improve accuracy and to give everyone a chance to race down the ramp / hill.

* A variation to be practiced is timing as the racers pass by a single point.

* Make a "train" of racers ( two students back-to-back on skateboards).

* Measure the total length of the "train".


Similar Triangles:




Measuring Speed: