Where are we going with this? The point of this deck is to give the background information and examples so that we can differentiate between substances (pure and mixtures) based on physical and chemical properties.
Two Main Types of Matter
Okay, then, let's get right to it!
Matter can be classified into two broad types: pure substances and mixtures.
Bet you thought I was gonna say "pure" and "impure", because… Logic… Think about it… If there are two types and one of them is "red" then then everything else has to be "not-red."
So…
The same is true for matter. If one type is pure substances, and the other type is mixtures, then mixtures must be substances that are impure. Because… Logic
Very good question! Here's two reasons as to why rest mass is a thing.
First off, you probably have heard of the theory of relativity. Part of that includes the concept that mass changes as the velocity of the object increases. So, the mass of an object isn't a constant. It is a function of velocity.
Does that mean you feel heavier if you are riding in a car?
No. There's a part of the equation that divides the square of velocity of the thing moving by the square of the speed of light. That pretty much equals zero if you are driving around in a car.
302 / 186,0002 = not much
The second reason that rest mass is a thing is… it's complicated…
Electromagnetic energy, such as light, is considered to have momentum as long as it is moving. Momentum is a function of mass. So… Does that mean light has mass? If light has mass, problems arise and it makes people's heads hurt, so it is convenient to say light has momentum but not mass, which is a paradox of sorts.
Generally, the argument discussion, concept, paradox can be satisfied by saying that light has no rest mass, meaning that once it stops moving, it has no mass. Thus, the concept of rest mass is useful.
Where are we going with this? The point of this deck is to give the background information and examples so that we can differentiate between substances (pure and mixtures) based on physical and chemical properties.
What is matter?
Not what is the matter… That's a different question.
Matter is all the physical stuff that makes up the universe.
If it is made of matter, it is a noun. However, not all nouns are made of matter, so… Within the common vernacular, if you can see, smell, taste, or touch it, it is matter.
Seems simple enough? Let's formalize this a little, then:
In the universe, matter includes any physical substance that possesses rest mass. Matter does not (even though they are things in the universe) include:
The lab will provide 3 trials in which force and distance are measured. Using the equation for work,
W = Fd
where W is work, F is applied force and d is distance through which the force was applied
it is relatively simple to calculate how much work was done. Introductory science students should remember that when two variables are placed beside each other without any operator, it is meant for them to be multiplied.
The lab will provide an initial distance and a final distance that will be used to calculate distance.
The measures in the video are hypothetical, but reflect realistic quantities. They are contrived for the sake of creating a virtual lab experience that do not require actual lab access. Instructions:
The virtual lab draws from the data in this video:
Watch the video and use the data within to complete the lab. The following link should open a COPY of a Google Doc into which you can type your answers.
In this article, the topic is the relationship between Newton's Second Law and Motion, and the displacement of an object.
The method here will demonstrate how to find the force needed to move an object.
How do you find the force needed given time (t), final displacement (df), initial displacement (di), initial velocity (vi), and the mass of the object?
Once again, it is necessary to combine two principles in order to see the full relationship.
You will have to find the rate of acceleration (a) using the distance equation, then use that to find the force (F).
So, you want to use
F=ma
to find F, but you don't have the a. That means finding a using the distance information given and the distance equation.
The distance formula is:
df = di + (vi )(t)+ 1/2(a)(t2)
So, we'll be doing two steps.
Step 1:
Use the distance equation to find a:
df = di + (vi )(t)+ 1/2(a)(t2)
Step 2:
Then use the calculated a with Newton's Second Law
F = ma
to find the force.
EXAMPLES
Example 1
Let's take a look at another example (even easier!) and work it out:
What force acts on a object with a mass of 10 kg, if it begins 5 meters from a mark and has an initial velocity of 25 m/s, and ends up a final distance of 227 m from the mark after an elapsed time of 6 seconds?
STEP 1
Find a where:
df = 227 m
di = 5 m
vi = 25 m/s
t = 6 s
df = di + (vi )(t)+ 1/2(a)(t2)
227 m = 5 m + (25 m/s)(6 s) + 1/2(a)(62) Combine some terms... and PEMDAS 227 m = 5 m + (25 m/s)(6 s) + 1/2(a)(6 s)2
227 m = 5 m + 150 m + 1/2(a)(36 s2)
227 m = 155 m + (18s2)(a)
Subtract 155 m from both sides...
78 m = (18s2)(a)
Divide both sides by 18s2 ...
78 m / 18s2 = a
4 m/s/s = a
Next, use THAT calculated a to find the Force (step 2 above):
NOTE
While this example shows how to find F when given distance information, the same process applies when asked to find the force given velocity information. However, you'd begin (Step 1) using the velocity information and formula to find a, the go on to Step 2 and solve for force. SUMMARY:
You gotta do it in steps!
This process requires doing the work in steps. Depending on what is given, you use the two formulas below:
F = ma
df = di + (vi )(t)+ 1/2(a)(t2)
So, read the problem, write down what is being looked for, write down what is given, THEN... use the two formulas. Two steps!
In this article, the topic is the relationship between Newton's Second Law and Motion, and this time, displacement will be the focus.
How do you find a total displacement when given time (t), initial displacement (di), initial velocity (vi), but instead of acceleration (a), you are given force (F) and mass (m)?
Once again, it is necessary to combine two principles in order to see the full relationship.
The distance formula is:
df = di + (vi )(t)+ 1/2(a)(t2)
However, to find final displacement, you need an acceleration(a), but you have mass and force.
Using Newton's Second Law, fortunately, will allow the calculation of a using the force and mass given.
So, we'll be doing two steps.
Step 1:
Use
F=ma to find a
Step 2:
Then use THAT in the distance formula.
df = di + (vi )(t)+ 1/2(a)(t2)
EXAMPLES
Example 1
Let's take a look at another example (even easier!) and work it out:
A force of 50 N acts on a object with a mass of 10 kg. If it has an initial displacement (di) of 10 m and has an initial velocity (vi) of 20 m/s, what is its final displacement after an elapsed time of 4 seconds?
The question tells us that we need to find final velocity (vf). But there is no acceleration given. So, do step 1 (above):
Find a where:
F = 50 N
m = 10 kg
F = ma
50 N = (10 kg)(a)
50 N/10 kg = a
5 m/s/s = a
Next, use THAT calculated a to find final velocity (step 2 above):
A motorcycle stunt rider needs to reach a final velocity of 799 m/s in order to make the jump needed for the scene in the movie. If she has an initial velocity of 10 m/s and the total mass of her and the motorcycle is 125 kg and if she can create a force of 100 N, how much time will be needed to achieve the needed final velocity?
On the surface, it looks (exciting, but also) like this could be hard to do.
IT'S NOT!
The velocity formula is very easy:
vf = vi + (a)(t)
In the problem above, you are looking for t and vf and vi are given. And then there's that mass and force...
You need an acceleration(a), but you have mass and force. Thankfully Newton did that thing:
F = ma
So, we'll be doing two steps.
Step 1:
Use
F=ma to find a
Step 2:
Then use THAT in the velocity formula.
vf = vi + (a)(t)
EXAMPLES
Example 1
Let's take a look at another example (even easier!) and work it out:
A force of 50 N acts on a object with a mass of 10 kg. If it has an initial velocity of 20 m/s, what is its final velocity after an elapsed time of 8 seconds?
The question tells us that we need to find final velocity (vf). But there is no acceleration given. So, do step 1 (above):
Find a where:
F = 50 N
m = 10 kg
F = ma
50 N = (10 kg)(a)
50 N/10 kg = a
5 m/s/s = a
Next, use THAT calculated a to find final velocity (step 2 above):
Find vf where
vi = 20 m/s
t = 8 s
a = 5 m/s/s
vf = vi + (a)(t)
vf = 20 m/s + (5 m/s/s)(8 s)
vf = 20 m/s + 40 m/s
vf = 60 m/s
Example 2
How about seeing it worked out?
SUMMARY:
You gotta do it in steps!
This process requires doing the work in steps. Depending on what is given, you use the two formulas below:
F = ma
vf = vi + (a)(t)
So, read the problem, write down what is being looked for, write down what is given, THEN... use the two formulas. Two steps!
