Angle of Elevation The angle of elevation is measured from a horizontal line looking up at something.

The Angle of Depression is measured from a horizontal line looking down at something.

An outdoor basketball backboard casts a shadow 17 1/3 feet long. The angle of elevation from a point at the end of the shadow to the top of the backboard is 35.8°. Find the height of the backboard. What would you want to do first?Draw a picture! 17 1/3 ft shadow h 35.8° Now you see that this is nothing but a right triangle trig problem. What trig function would you use that relates the angle and side you know to the side you want to know?

Many physical phenomena can be modeled with simple harmonic motion. the swinging of a pendulum radio and television waves light and sound waves water waves a spring-mass system

The amplitude is |a|. The frequency is the number of oscillations per unit time. It is the reciprocal of the period.

Simple harmonic motion can be expressed with either sine or cosine but since this object starts at 4 when t = 0, cosine makes sense. If you used sine, you'd have to use a phase shift to have a different value than 0 at t = 0. An object attached to a coiled spring is pushed up a distance 4 units from its rest position and then released. Assuming that the motion is simple harmonic with period 2 seconds, write an equation that relates the displacement d of the object from its rest potion after t seconds. Assume that the positive direction of the motion is up.

If we knew the equation of motion for an object, we could determine some things about it. The equation modeling the motion of an object is: This negative tells us that after t = 0, it will be stretched down first Since we know , we can find the period This tells us that the motion will repeat every seconds. 1.6 What is the frequency? It is the reciprocal of the period so This means in one second, it has completed.64 oscillations..64