Lecture 1: Basics Of Physics Flashcards
Newton’s First Law of Motion
An object at rest remains at rest until a force acts upon it
AKA – law of inertia
What is Newton’s first law of motion also referred to as?
Law of inertia
The greater the mass of an object… The ___ force is required to get it moving
More
Velocity
Describes how the position of an object changes with time
Velocity is a ___ quantity
Vector quantity
Is mass a vector quantity?
No–mass is a scalar quantity
What are vectors?
Vectors have both magnitude and direction
What is a resultant vector?
When you add two vector quantities together…for example, if you are walking 5 mph on a train going 30 mph (both in the same direction), then the resultant vector quantity is 35 mph.
Acceleration
Describes how velocity changes over time
Acceleration is a ___ quantity
Vector quantity–has both magnitude and direction
Newton’s second law of motion
Force = mass X acceleration
Acceleration is dependent upon what two variables?
1) the net force acting upon the object
2) the mass of the object
F = ma (Newton’s second law of motion)
What is the unit of measure for acceleration?
Meters/second ^ 2
What is the estimated force of gravity?
9.8 m/s^2
What is force?
A push or a pull; related to mass
Force =
Mass X acceleration (Newton’s second law of motion)
What is gravity?
Universal attraction between all objects; related to Newton’s third law of motion
What is Newton’s third law of motion?
For every action, there is an equal and opposite reaction
What is weight?
Gravitational force exerted on an object by another larger object
Weight =
Mass X gravity (9.8 m/s^2)
What is pressure?
Force per unit area
Pressure =
Force/area
How can you increase pressure?
1) Increase the applied force (push down more)
2) Decrease the area that force is applied in
How can you decrease pressure?
1) Decrease applied force
2) Increase area
Units of pressure–PSI
Pounds per square inch
What is atmospheric pressure (1 atm)?
Standard temperature and pressure
1 atm =
=760 torr
=760 mm Hg
What is an Aneroid gauge?
- Gauge seen on old oxygen tanks
- Greek in origin–aneroid means “without water/liquid”
- Change in dial relies on expansion and contraction of bellow system
What is a Bourdon gauge?
- Aneroid style gauge–no liquid inside
- Measures gas pressures
- Seen on oxygen, air tanks
What does the Bourdon gauge measure?
It measures the pressure difference between the pressure exerted by the gas in the tank versus the pressure exerted by the gas in the atmosphere.
When the Bourdon gauge reads ‘0,’ is there any pressure left in the tank?
YES–there is still gas in the tank that is exerting the same amount of pressure as atmospheric pressure. Once it reads 0, it still has the equivalent of atmospheric pressure in there (14 psi = atmospheric pressure).