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28 Cards in this Set
- Front
- Back
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What is science? |
Resulting from human curiosity, an organized body of knowledge that describes the order within nature and the causes of that order. An ongoing human activity that represents the collective organizing and condensing this info into laws and theories. The Rules of Nature. A was of knowing about he world and making sense of it. (txtbk pg. 1). |
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Why are Equations guides to thinking? |
They integrate science in mathematics in ways that show the connections between concepts in nature. Example: F=ma is the same as saying "Newtons second law: Force is equal to the mass of an object multiplied by the objects acceleration". |
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What steps are common to various methods of inquiry know as the "Scientific Method"? |
1. Observe: recognize a ?? or puzzle. 2. Question: form a hypothesis ( "maybe" phrase) 3. Predict: based on knowledge, what happens? 4. Test Predictions: measurable experiments 5. Conclusions: Make a simple general rule based on hypothesis, predictions, and experimental findings. |
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What are some science based methods that advance Science? |
Scientific Method (organization of Cause/Effect) Scientific Attitude (Truthful assertions or facts that be proved or disproved)
(txt pgs. 3-5)
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What is the difference between speculation and a scientific Theory? |
Speculation is an unproved belief or assertion. Scientific Theory is based on findings and facts that have been organized into a rule that is based on what can be proven right and wrong. (txt. pg.5) Facts are revisable data. Theories interpret facts. Experimentation, not philosophical speculation is the test of truth (txt. p. 16) |
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What is the importance to science of the following historical figures:
Aristotle (384-322 BC) Nicolaus Copernicus (1700s) Galileo (1564-1642)
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Aristotle: (txt p.4, 15) Copernicus: (txt. p.2) Galileo (txt. p.16)
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Describe Force |
Force is a push or a pull on an object. (txt. p.16)
It is a vector quantity with both magnitude (how much) and direction. An arrow indicates direction of the force, and it's length represents magnitude. (p. 19) |
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Describe Inertia |
the property of an object to resist change in motion. Think about the frictionless ball rolling forever in one direction. (txt. p.16)
The greater the mass of an object, the greater the objects inertia (p. 17) |
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What is the difference between mass and weight |
Mass is the amount of matter in an object, also the measure of the inertia, or sluggishness that an object exhibits in efforts to change it's state of motion in any way. The mass of an object is not affected by variables like gravity. Your mass on the moon is the same as on earth, and is often measured in Kilograms. Weight is the object mass pulled by gravity. (p.17) |
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What is friction? |
resistance force that opposes motion. (p.23)
Friction always acts in a direction that opposes motion. Friction occurs with solids, liquids and gasses (all states of matter)
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What are the standard units of measurement for weight and mass? What is their relationship? |
mass=kilograms wt=pounds N=Newtons 1kg=9.8 N They are directly proportional to each other. If the mass of one is doubled, the weight is doubled. (p. 17 and 18). mass is not to be confused with weight or volume. The element Lead has a much higher mass than the element Carbon. |
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What is Net Force? |
Objects don't change motion unless a force acts. Net force is the totality of forces acting on an object.
Examples of these forces could be gravity, friction, air density, pushing, pulling or stretching force like tension (p.19, 21) |
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How can a net force of zero be accomplished? |
If the forces act together in a way that prevents motion of an object (push/pull example of the box. p.19). In the flour bag ex. (p.21) the two main forces at work are tension and gravity. Tension is upward, gravity downward. They oppose each other equally with a net force of zero. See also Equilibrium. |
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Explain Equilibrium, or Mechanical Equilibrium |
When the forces acting on an object prevent it's motion and it is at rest. This is called the equilibrium rule and is symbolized by (sigmaEF=0)
The sigma symbol ( ) stands for "the vector sum of " and "F" stands for force. Also see the example of Burl and Paul on p. 20.
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A book lying at rest on a table is an example of what principle? |
Mechanical equilibrium. The downward gravity (a force) and the support (a force) of the table to keep it off the floor oppose each other equally. Support force is also known as Normal Force (p.22) |
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How does a bathroom scale illustrate mechanical equilibrium? |
The downward force (gravitational attraction pulling on your body mass) is equalized by upward (holding you off the floor) force of the scale support or normal force. (p.22) |
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What is another term used to describe an object in mechanical equilibrium that is stationary? |
Static equilibrium. (p.23) |
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How is dynamic equilibrium different from static equilibrium? |
An object in motion, with no other forces acting on it to change direction or speed (both direction and speed are CONSTANT) is in dynamic equilibrium. Static means "not moving". (p.23)
A car, moving at 30 mph due East, is an example of dynamic equilibrium. When it slows, or changes direction, this is no longer the case. |
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When moving a desk in a straight line from point A to point B in an empty room with no wind or water, what is being accomplished in the realm of physics? |
Enough Force has to be applied to overcome friction (the ground resistance) and object inertia (gravity/mass). If this is done at a constant speed, then the desk is also in dynamic equilibrium. (p.23) |
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Speed= Distance covered ------------------------- travel time |
Units used to measure speed: ki/h kilometers per hour mi/h miles per hour the "/" symbol is read as "per" meaning "divided by"
car instantaneous speed is read on the odometer
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Average Speed = total distance traveled --------------------------------- travel time |
total distance covered = avg spd x travel time
speed is not a vector measurement because it doesn't include DIRECTION. |
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Velocity is a vector quantity measurement because.... |
to determine velocity it is necessary to know direction and speed.
includes magnitude (speed in this case) also known as a vector quantity.
velocity is straight line, constant speed and direction. Motion with no acceleration. (p.26) |
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Why is motion relative? |
Everything is in constant motion, even when we think we are standing still. A car is moving at 50 mi/h relative to the road. When sitting still in a chair we are moving at 100,000 ki/h relative to the sun. Every motion is in relationship or relative with something else. (p.26-27) |
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A ball rolling down an incline is best demonstrating velocity or acceleration? |
Acceleration As the ball rolls down the inclined plane, it's velocity changes, since the ball's speed increases the closer it gets to the bottom of the incline. The lack of constant speed and direction makes the incline a poor example of velocity. Acceleration is about increases in speed in a linear direction.
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what does:
a= delta v ----------- mean? delta t
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a= acceleration delta ( ) means change v=velocity t=time
this is the formula for determining acceleration of an object where velocity and time interval are known. (p.27) |
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what does:
v= at mean?
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velocity = acceleration x time interval (p.28)
example:
a= delta v = 5 km/h = 5km/h * s ----------- -------- ----------- delta t 1 s |
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When can speed and velocity be used interchangeably? (as though they were the same thing) |
Speed and velocity can be used interchangeably when the object moving is in linear (straight line) motion. When direction doesn't change, acceleration can be expressed as the rate at which SPEED changes. So, in formulas that fit this definition, speed can be used as "v" or velocity values. (p.28) |
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What is free fall? |
Objects falling toward gravity (rock, book, glass) increases it's speed as it moves toward gravity (earth). Objects near each other fall at the same rate of acceleration (delta speed / time interval). If gravity is the only force at work in the fall, which on earth is 10m/s each second, the object is in free fall. Falling object + only gravity= free fall (p.28). |
