Stain Measurement & Calculating Angles of Impact (Screencast)

In this learning object the student will learn how to measure a stain and calculate angles of impact. Determining the angle of impact for bloodstains takes advantage of the trigonometric functions (Sine function).

A mathematical relationship exists between the width and length of an elliptical bloodstain which allows for the calculation of the angle of the impact for the original spherical drop of blood.

Given well formed stains we can accurately measure the width and length by simply dividing the stain along it’s major and minor axis. The opposite halves would be generally equal to each other which aids in establishing the impact angle.

Learners examine the use of the tolerances displayed in a title block by calculating the minimum and maximum allowable size of a fabricated part. In a brief quiz, students determine whether a part is usable or should be scrapped.

The Effect of Temperature on the Vapor Pressure of a Liquid

Learners examine how vapor pressure is calculated. The vapor pressure of a liquid increases with increasing temperature. If the heat of vaporization and the vapor pressure at one temperature are known, the vapor pressure at a second temperature can be calculated.

The student studies the method to calculate complex power where the Vrms of a circuit is multiplied by the complex conjugate of the total circuit current. Several examples are given, along with the power triangle.

Buying a Car: What It Really Costs with Finance Charges (Screencast)

In this learning activity you'll calculate the difference in the total cost of a new car when using cash and when paying for the car with a 60-month loan.