Updated December 4th, 2021 This is your class landing page, you will want to come here every week to check for any class announcements. Make certain you read everything on this page and understand completely all the directions. You can access past weeks announcements in their respective Quarter pages.
Summary of Week #14
Left: for calculating the range of a projectile.
Right: for calculating the vertical distance an object falls.
This week we introduced the notion of motion in two dimensions. Recollect from Tuesday's class, when discussing parabolic, or projectile motion, we need to remember that projectiles travel along a path (called a trajectory) with velocity vectors comprised of both x- and y- components. Motion doesn't occur only along the x-axis (horizontally) or only along the y-axis (vertically), but rather occurs most often along both axes - or at an angle.
We can analyze the motion of a projectile along either axes, individually. As an example, if we are curious as to the range (horizontal distance) a projectile travels, we can use the left--most equation at right. In this, "d(sub x)" represents the horizontal distance the projectile travels, while "v(sub x)" is the x-component of velocity, and "t" is the time from which it is launched until it hits the ground.
Similarly, we can analyze the motion of a projectile along it's y-axis, by using the right-most equation above, where "d(sub y)" is the distance an object travels along it's y-axis, "a" is the acceleration due to gravity (9.8 m/ s^2), and "t" is the time interval of the fall.
The range at which a projectile travels is dependent upon two things (1) the velocity wherein it was launched and, (2) the launch angle. If you have been keeping up on the reading and videos, you will already know that the optimal angle for the greatest range of a projectile is 45-degrees.
What to expect in Week #15
Fig. 1. The motion of a projectile, has both x- and y- components.
This week we are going to perform the laboratory on Projectile Motion - do make certain you read this lab before coming to class so you are ready for action.
After we collect all of our data as to the range a steel ball will travel when launched at various angles, we will graph it, and then make a prediction from that graph (that's why we make graphs). We will predict the launch angle of the ball, if we want it to land a specified distance from the launch apparatus. Then we will test our theoretical assumptions against our experimental outcomes, and calculate percent error.
Fig. 2. The ball on the string is experiencing a centripetal force.
You will need to complete at home on your own, the Skill & Practice 6C; there are two key terms (and equations that accompany them) that you should know:
Angular speed - describes how fast something rotates and is expressed mathematically as:
Angular speed = rotations or degrees/ time
Linear speed - describes how fast a revolving object travels and is calculated by:
Linear speed = 2 (pi) r/ t
On Thursday we will collect data for the Centripetal Force laboratory. Make sure before this class that you:
Print this lab out, read it and bring to class with you
watch the Section 6.3 video addressing Centripetal Force
complete as many homework problems as possible from Section 6.3, so you know how to calculate centripetal force.
Check-off List of Things to Do:
Make sure you do the following before classes for Week #15 Tues, December 7th:
Print out, read, and bring to class Projectile Motion laboratory (linked right)
Re-watch Section 6.1 video, know conceptually the variables involved in projectile motion
Turn in Quiz #14 (which was handed out last Thursday), making sure parents sign on quiz where indicated and seal across envelope
Thurs, December 9th:
Complete at home on your own Skill & Practice 6C
Watch Sections 6.2 and 6.3 videos
Print out, read, and bring to classCentripetal Force laboratory
Prepare for in-class Quiz #15
Week 15 Resources/ Assets
Use the "Class Questions Forum" to ask any questions about assignments, labs, quizzes, due dates, etc.