Introduction to Uniformly Accelerated Motion with Examples of Objects in UAM
Summary
TLDRIn this engaging physics class, Mr. P introduces the concept of uniformly accelerated motion (UAM), explaining that it involves constant acceleration. He provides examples such as a ball rolling down an incline or a person falling from a plane. Mr. P then presents the four UAM equations and their five key variables: final velocity, initial velocity, acceleration, time, and displacement. The students participate in a light-hearted back-and-forth while learning that if they know three variables, they can calculate the other two. The lesson concludes with a preview of solving UAM problems in the next class.
Takeaways
- đ Mr. P begins the lecture by introducing uniformly accelerated motion (UAM), where acceleration is constant.
- đââïž Examples of UAM include a ball rolling down an incline, a person falling from a plane, or a toy being dropped in water.
- âïž Although none of these examples are perfectly uniform due to external factors like friction and air resistance, they are close enough for educational purposes.
- âïž Mr. P introduces the four UAM equations that describe uniformly accelerated motion, covering velocity, time, acceleration, and displacement.
- đ Bobby lists the five key variables in the UAM equations: final velocity, initial velocity, acceleration, time, and displacement (delta X).
- đą Mr. P explains that by knowing three out of the five UAM variables, you can solve for the remaining two.
- đ Using base SI units (meters and seconds) in UAM calculations reduces errors, though it isn't mandatory in all cases.
- đ€ Mr. P uses a question-answer approach with students to reinforce the understanding of the number of variables and equations in UAM.
- đ Mr. P concludes that knowing three variables allows for solving the others, leaving students as 'happy physics students.'
- đ The lecture ends with a teaser for the next session, which will include solving an example problem related to uniformly accelerated motion.
Q & A
What does UAM stand for?
-UAM stands for Uniformly Accelerated Motion, which refers to an object moving with a constant acceleration.
What are some examples of objects in uniformly accelerated motion?
-Examples include a ball rolling down an incline, a person falling from a plane, a bicycle braking, a ball being dropped from a ladder, and a toy baby bottle being released in water.
Why does Mr. P say none of the examples are perfectly uniformly accelerated motion?
-Mr. P acknowledges factors like friction, non-constant inclines, air resistance, and non-perfect braking forces, which deviate from perfect UAM. However, he emphasizes that these examples are close enough for the purposes of teaching the concept.
How many UAM equations are there and what do they describe?
-There are four UAM equations. They describe relationships between velocity, acceleration, time, and displacement for objects in uniformly accelerated motion.
What are the five variables involved in the UAM equations?
-The five variables are final velocity, initial velocity, acceleration, time (change in time), and displacement (change in position).
What suggestion does Mr. P give regarding the units used in UAM equations?
-Mr. P suggests using base SI units, specifically meters and seconds, because it reduces the chances of making mistakes in the calculations.
If you know three of the five UAM variables, what can you do?
-If you know three of the five variables, you can calculate the remaining two unknown variables using the UAM equations.
Why does Mr. P emphasize the number of variables and equations?
-Mr. P emphasizes the number of variables (5) and equations (4) to show that by knowing three variables, you can always solve for the other two, leaving you with a 'happy physics student.'
What does Mr. P mean when he says 'delta means change in'?
-In physics, the Greek letter delta (Î) is used to represent a change in a quantity. For example, ÎX represents the change in position (displacement).
What does Mr. P promise for the next lecture?
-Mr. P promises that in the next lecture, the class will go through and work on an example problem related to uniformly accelerated motion.
Outlines
đ Introduction to Uniformly Accelerated Motion
Mr. P begins the class by introducing the topic of uniformly accelerated motion (UAM). He explains that UAM refers to an object moving with constant acceleration. Various real-life examples like a ball rolling down an incline, a person falling, or a toy bottle in water are used to illustrate this concept. Despite imperfections like friction or air resistance, these examples are close enough to UAM for the purposes of this class. Mr. P acknowledges these imperfections but emphasizes their irrelevance to the current lesson.
𧟠UAM Equations and Variables
Mr. P introduces the four main equations that describe objects in UAM and emphasizes the five key variables: final velocity, initial velocity, acceleration, time change, and displacement. He walks through each equation and asks Bobby to list the variables. Bo corrects Bobby's terminology, and Mr. P clarifies that delta X represents displacement. He advises students to use SI units like meters and seconds, suggesting that this minimizes errors in calculations.
â Understanding the UAM Problem-Solving Process
Mr. P quizzes the class to reinforce the number of UAM variables and equations. He repeats that if students know three out of the five variables, they can calculate the other two. Through some back-and-forth with the students, he emphasizes that knowing three variables leads to one 'happy physics student,' symbolizing their ability to solve UAM problems. The class participates actively, confirming the core ideas behind the variables and equations.
đ Wrapping Up and Looking Forward
Mr. P concludes the lecture by reinforcing the number of UAM variables and equations through repetition and humor, ensuring the students understand the concept. He then previews the next class, where they will solve an example problem on uniformly accelerated motion. The lesson ends with a light-hearted tone, and the voiceover directs students to find lecture notes at FlippingPhysics.com, advising them to 'enjoy lecture notes responsibly.'
Mindmap
Keywords
đĄUniformly Accelerated Motion (UAM)
đĄAcceleration
đĄVelocity Initial
đĄVelocity Final
đĄDisplacement (ÎX)
đĄChange in Time (Ît)
đĄUAM Equations
đĄSI Units (Meters and Seconds)
đĄPeanut Gallery
đĄPhysics Student
Highlights
Introduction of the topic: Uniformly Accelerated Motion (UAM), which is defined as an object moving with constant acceleration.
Examples of UAM include a ball rolling down an incline, a person falling from a plane, and a ball being dropped from a ladder.
Clarification: While real-world examples may not be perfectly uniform due to friction and other forces, they are close enough to be considered UAM for educational purposes.
The 4 UAM equations are introduced, which describe the motion of an object in uniformly accelerated motion.
Breakdown of the first UAM equation: Final velocity is equal to initial velocity plus acceleration times change in time.
Explanation of the second UAM equation: Displacement equals initial velocity times change in time plus half the acceleration times the change in time squared.
Discussion of the third UAM equation: Final velocity squared equals initial velocity squared plus two times acceleration times displacement.
Introduction of the fourth UAM equation: Displacement equals half the sum of final and initial velocities multiplied by the change in time.
Identification of the 5 variables in UAM: Final velocity, initial velocity, acceleration, change in time, and displacement.
Clarification that delta X represents displacement or change in position.
Advice to use base SI units (meters and seconds) when solving UAM equations to minimize errors.
Important insight: If you know 3 out of the 5 UAM variables, you can calculate the remaining 2 variables.
Repetition of the core concept to solidify learning: There are 5 UAM variables, 4 UAM equations, and knowing 3 variables helps you determine the other 2.
Humorous conclusion: After solving the equations, you're left with 1 happy physics student.
Teaser for the next lecture: The class will work through an example problem of uniformly accelerated motion.
Transcripts
Bo: Hey, guys.
Billy: Hey, Bo.
Bobby: Hi, Bo.
â« (lyrics) Flipping Physics â«
Mr. P: Ladies and gentlepeople,
the bell has rung, therefore class has begun,
therefore you should be seated to your seat
ready and excited to learn about
uniformly accelerated motion.
Bo: Absolutely.
Bobby: Yes.
Billy: Oh boy.
Mr. P: Uniformly accelerated motion.
An object in UAM, or uniformly accelerated motion,
is an object that is moving with an acceleration
that is uniform, an acceleration that is constant,
an acceleration that is equal to a number and
that number does not change.
There are all sorts of objects that are
in uniformly accelerated motion, or UAM.
You could have, for example, a ball
rolling down an incline.
A person falling from a plane.
A bicycle on which you have applied the brakes.
A ball being dropped from the top of a ladder.
Or even a toy baby bottle, being released
from the bottom of a bath.
All of these are examples of objects
experiencing uniformly accelerated motion.
Yes, I know there is friction.
I know the incline isn't perfectly constant.
I know that the air exists.
I know that the water is actually going to apply
large drag force.
I also know that the brakes aren't going to
apply a perfectly constant braking force.
Therefore, none of these examples are perfectly
uniformly accelerated motion, but we can also
talk about the fact that we live in a non-constant
gravitational field, that the bike is actually
travelling on the surface of the planet, which is the
shape of a sphere, which means it's
not a euclidean surface.
We can also talk about the fact that travelling
you can spell with 1 or 2 "l's".
But none of this is stuff that we're gonna
talk about today because it's close enough.
All of these examples are very close to
uniformly accelerated motion, and therefore
we can consider it for the purposes of this class,
for all of them to be uniformly accelerated motion.
OK?
Bobby: Who is he talking to?
Bo: I don't know.
I didn't think anybody else was here.
Billy: Peanut gallery.
Have you guys never seen the peanut gallery?
Mr. P: Alright, moving on.
Here are the equations that describe an
object moving in uniformly accelerated motion.
There are 4 UAM equations.
I have written them right here and now I'm
going to walk my way through each one of the equations.
Velocity final is equal to velocity initial
plus the acceleration times the change in time.
Displacement is equal to velocity intial
times the change in time plus one half times the
acceleration times the change in time^2.
Velocity final^2 is equal to velocity initial^2 plus
2 times the acceleration times the displacement.
And the change in position is equal to one half times the
quantity of velocity final plus velocity initial
that can be multiplied by the change in time.
Bobby, there are 5 variables.
Could you please identify all 5 varibles
in these 4 equations?
Bobby: OK, let's see, there's velocity final
and velocity initial, acceleration, what else?
Change in time and delta X.
Bo: Words, not letters.
Bobby: Yeah, that's change in displacement.
Bo: Delta X is displacement, it's not
change in displacement.
Bobby: The last one is displacement, or
change in position.
Thanks, Bo.
Bo: You're welcome.
Mr. P: Yes, the 5 variables are velocity final,
velocity initial, acceleration, change in time,
and displacement, or delta X which means
the change in position because delta means
"change in" and X means "position".
Now, one thing that I do suggest when you use
the UAM equations is that you always use
base SI dimensions or meters and seconds.
Now, it's not actually mandatory, but I find
that students make many fewer mistakes
when they use meters and seconds
in the UAM equations.
Every once in awhile you don't have to,
but for the purposes of this class, we
are always going to use meters and seconds.
Now, the way it works is this.
If you know 3 out of the 5 UAM variables,
you can actually figure out
the other 2 unknown variables.
So, here's how it works.
Everybody ready?
Billy: Yeah.
Bobby: Sure.
Bo: Ready for what?
Mr. P: Class, there are how many
uniformly accelerated motion variables?
Billy: Uh...
Bobby: Ah...
Bo: 5.
Mr. P: OK, um, let's try that again.
Class, there are how many uniformly
accelerated motion variables?
Billy, Bobby, Bo: 5.
Mr. P: And there are how many UAM equations?
Billy, Bobby, Bo: 4.
Mr. P: And if you know how many of the variables?
Billy, Bobby, Bo: 3.
Mr. P: You could figure out the other?
Billy, Bobby, Bo: 2.
M. P: Which leaves you with 1?
Bobby: Uh?
Billy: Answer?
Mr. P: Not answer.
Turns out that because there are actually 2 unknown
variables, you could actually have more
than 1 answer, so what you are actually
left with is 1 happy physics student.
Bo: Ugh.
Billy: That's me.
Bobby: Yeah.
Mr. P: Alright, 1 more time.
There are how many UAM variables?
Billy, Bobby, Bo: 5.
Mr. P: And there are how many UAM equations?
Billy, Bobby, Bo: 4.
Mr. P: And if you know how many of the UAM variables?
Billy, Bobby, Bo: 3.
Mr. P: You could figure out the other?
Billy, Bobby, Bo: 2.
Mr. P: Which leads you with 1?
Billy, Bobby, Bo: Happy physics student.
Billy: Yeah.
Mr. P: That's right, 1 happy physics student.
In our next lecture, we're gonna go through
and work through a problem, an example problem
having to do with uniformly accelerated motion.
I hope you enjoyed learning with me today, class.
I enjoyed learning with you.
Voiceover: Lecture notes are available at Flippingphysics.com
Please enjoy lecture notes responsibly.
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