What is Motion and how can we tell that something is moving?

Is it in motion? Look at the energy drink can sitting on my desk. You and your table needs to answer the following. 1. Is the can in motion relative to you and your classmates? 2. Is the can in motion at all? 3. Does the can’s motion depend on where I look at it from? 4. If the can is moving so fast through space why doesn’t it appear to be moving to us?

Motion and Force Motion: Motion occurs when something changes position relative to a reference point, measured by distance and time. But, what is a reference point?

- Describing and Measuring Motion Determining When an Object is in Motion Have you ever watched a large truck pass you on the highway and felt like you were going backwards? Whether or not an object is in motion depends on the reference point you choose & if the distance between the object and the reference point is changing. Figure 2- Page 8

Frame of Reference A frame of Reference (reference point) is the object we use to compare distances, displacements, speeds, etc. To measure movement, some point must be considered as nonmoving. Earth is the most common frame of reference. Examples: buildings, trees, mountains, people standing, etc. It can sometimes be misleading, (think of the sun rising and setting) so be careful.

Reference Point: the point from which movement is determined In the image, if the tree is the reference point, the car is moving away from from the reference point as it goes from position 1 to position 2.

Inertia & Newton’s 1 st Law An object’s inertia causes it to continue moving the way it is moving unless it is acted upon by a force to change its motion. A body at rest remains at rest and that a body in motion remain in motion unless acted upon by an outside force.

Looking Back to our Activities How can you relate what we did in our activities to Newton’s law and Inertia? Newton’s 1 st Law & Inertia exploration using marbles and car/pennies To Run or Not to Run?

How & Why Did the Marble Move? The marble was at rest until you applied a force, moving the box and since the marble is in the moving box the marble will move with the same force.- Newton’s 1 st law

Because of Newton’s Law you should wear a seatbelt and a helmet!

Running to gain distance If you wanted to throw a ball as far as possible you would want to run with a ball prior to throwing it! The ball gets your speed before you even try to release it. For example: If you run at 5m/s, then the ball will get the additional speed of 5m/s when you throw it. The ball’s speed is the sum of your speed before releasing the ball, 5/m and the speed of the ball as it travels from the force you applied to throw it.

What is a force?