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What direction?. Practicing with directionality. Defining Directions. Three types of motion Linear (along a straight line) Two Dimensional (along a plane) Three dimensional (Moving left/right, forward/backwards, up/down)
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What direction? Practicing with directionality
Defining Directions • Three types of motion • Linear (along a straight line) • Two Dimensional (along a plane) • Three dimensional (Moving left/right, forward/backwards, up/down) • In kinematics, we have to be able to describe the direction of an object’s motion. How do we do this?
Linear Motion • What is the difference between forward and backwards? • Nothing!!! It’s a matter of perspective • How do we indicate there is a difference? • We say one direction is positive and one direction is negative! • Does it matter which is + and which -? • Not even the tiniest bit!
Linear motion • Include a dual headed arrow • Make one direction positive and one direction negative How do you describe? I walked 5 m to the right I walked 10 m to the left - +
Compass Draw a compass to help you find the answers to these questions. • I am facing North, I turn 90° counter-clockwise. Which direction am I now facing? Is this direction positive or negative? • I am facing South West. I turn counter-clockwise 180°. Which direction am I now facing? Is this direction positive or negative? • I am facing South. I turn three right angles clockwise. Which direction am I now facing? Is this direction positive or negative? • I am facing North West. I turn one and a half right angles clockwise. Which direction am I now facing? Is this direction positive or negative? • I am facing South West. I turn 90°counter-clockwise. Which direction am I now facing? Is this direction positive or negative?
Other 2-d angles • We can describe any angle that’s given by referencing North, East, South, West and giving a rotation • There are two parts: • Reference direction • Any of the points on a compass (N, E, S, W) • Rotation info • Measure of rotation and direction
Two ways to describe • [reference rotation] • [N 30E] • [rotation of reference] • [30E of N]
[N30E] or ?? Reference Direction Rotation of 30 towards east
Angles Complete the Activities on this website to practice measuring angles. http://www.mathsisfun.com/geometry/protractor-using.html
Move Around! • Complete the following in partners: • Using a compass app on your phone figure out which direction is North. • On a blank piece of paper label the directions of the compass and tape it onto your desk (North must actually be pointing North). • Have one partner wander to another location in the room and stop. • Estimate their displacement by • Determining their direction using your paper. • Estimating how far, in metres, they are from you. • Measure their actual displacement using a metre stick and verifying their direction with a compass app. (we will practice measurement again next week – just do your best)