Lesson #3

Lesson #3
E.Q: How to Describe motion in real-life?

Kinematic is MOTION

MOTION IS A CHANGE IN LOCATION BASED ON A REFERENCE POINT

WITHOUT A FRAME OF REFERENCE, HOW DO YOU KNOW MOTION OCCURED?

• Have you ever been sitting as a stoplight and the car next to you moves slowly forward and you think your car is moving??

• You were using the other car as your point of reference.

• If you are looking at the stoplight, or a tree on the side of the road, then you do not feel like you are moving, you know the other car is moving. Right?

Think about being on a school bus and holding a basket ball. If you are on the bus, the basket ball is not moving in relation to the bus. But if you are on the street, looking in the bus and noticing the basket ball, as the bus moves down the street, the basket ball moves at the same speed and direction as the bus!

Multiple Choice

If the bus in the example drives .25 miles east, how far does the basket ball move in relation to the bus and the student holding the ball?

• .25 miles

• It does not move

• .50 miles

• .125 miles

Multiple Choice

If the bus in the example drives .25 miles east, how far did the basket ball move in relation to the person standing on the street?

• .25 miles

• It is not moving if someone is holding it.

• 0 miles

• .50 miles

Distance

• Distance refers to “how much ground an object has covered” or the length of its motion.

• Distance is a scalar quantity

Distance will only tell you how much you have travelled.

Example:

187km

3 miles

12 steps

Let's Try It!

Olivia walked 2 miles to the local park. Then she walked 4 miles to the mall. Then she walked 6 miles back home. What is the total distance she walked?

Displacement

• Displacement refers to "how far out of place an object is."

• Displacement is a vector quantity.

Let's Try It!

Let's look at the previous problem:

Olivia walked 2 miles North to the local park. Then she walked 4 miles East to the mall. Then she walked 2 miles South and then 4 West miles back home. What is Olivia's displacement?

Multiple Choice

Here is a harder one. A student leaves their house and drives 5 miles north to the gas station to get gas for their grandmother's lawn mower. They then drive back south 2 miles past their house to their grandmother's house to mow their grandmother's lawn. (What a great kid!) What was the distance traveled? Read the question carefully. It helps to draw pictures of these problems.

• 5 miles

• 7 miles

• 2 miles

• 12 miles

Multiple Choice

If you run around the school track, what distance did you run? What was your displacement?

• Distance =

  440 yds

  Displacement = 440 yds

• Distance =

  440 yds

  Displacement =

  220 yds

• Distance =

  440 yds

  Displacement =

  0 yds

Group Work