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This text is meant to accompany class discussions. It is not everything there is to know about uniform circular motion. It is meant as a  prep for class. More detailed notes and examples are given in the class notes, presentations, and demonstrations (click here.)

Click for the questions that go with this reading
Impact Velocity ...Finding Magnitude and Direction

The YouTube video below will describe how to find the impact velocity's magnitude and direction. This is the video link, http://youtu.be/OeIfR-oqcVg

This video focuses on the impact velocity, but this process of finding the vertical and horizontal components and then using right triangle trigonometry and Pythagoreans theorem can be applied for any point in the motion where you can calculate the velocity's components. To calculate a projectile's direction, you MUST USE VELOCITY COMPONENTS. This is the only method that works because the path of the ball is curved and not a straight line.

 

Example Problem
  • Question
  • Answer
  • Your Paper
  • Video Solution

At the beginning of a football game you observe the opposing team’s place kicker kick the ball from 25 m away from the goal posts. You think, “Wow. What a kick.” You bring out your camera and record his kick. You use your computer in the locker room and observe that he kicks the football at 22.0 m/s.

During the game the opposing team has the ball with the score tied. Your opponents have the ball at a spot where the ball will have to travel 33.0 meters along the ground to reach the goal posts. The place kicker is getting ready to kick. The coach calls time out because what he decides for the team to do depends whether of not he thinks the ball will go over the goal posts. He turns to you and says, “...If the kicker hits the ball at a 45 degree with the ground will it go over the goal posts assuming they are 3.048 m above the ground?” What do you tell him?

The ball will make it over the goal post. It will be at a height of 10.95 m at a range of 33.0 m.
Solution on your notebook paper

by Tony Wayne ...(If you are a teacher, please feel free to use these resources in your teaching.)