California Middle School Mathematics Concepts and Skills: Course 2

Ask students to look for examples of mathematics as they watch Futures Channel Movie #1002 The Pterodactyl Flies Again. Discuss some answers, then ask this question: When an aircraft, or a bird, dives to the ground, what happens to its velocity? Guide discussion to agreement that the velocity will increase, and that the greater the height of the dive that faster will be the velocity.

Explain to students that in fact the relationship between velocity and height of the fall is given by the equation v² = 19.6 x height (with height measured in meters and velocity in meters per second). For example, if the height of the dive is 100 meters, then the velocity should be given by the equation v² = 1960.

Explain that solving this equation means finding a number, v, that when it is multiplied by itself gives a product of 1960. Tell students that that number is called the square root of 1960. Ask students to verify that the square root of 1960 is about 44.25. Once they have done this, do a few more examples, then tell students they will be learning more about square roots in this chapter.