Gravity, Force, and Pressure Flashcards
I got this stuff from the study guide and notes I took in class.
How could kinetic molecular movement be applied to pressure?
When gas molecules collide with the walls of the container, the collision is elastic. ie. Momentum before collision = Momentum after collision. Hence, the gas molecule imparts a certain momentum to the wall. As there are a large numbers of gas molecules, a larger number of molecules collide with the wall every second. Change in momentum per unit time (per second) is force. Force per unit area is pressure. (gay answer, sorry)
What is atmospheric pressure and what causes it?
Gravity pulls on all objects, including the atoms and molecules of the atmosphere. Because these atoms and molecules have low mass, they have low gravitational pull but nonetheless are pulled toward the Earth. The cumulative effect of gravity on atmospheric gases give rise to atmospheric pressure.
What is the difference between mass and weight?
Mass is the total of all matter in an object, it does not change. Weight is the product of mass multiplied by gravity & it will changes if location is changed (i.e. earth v/s moon).
What is force?
force = mass x acceleration force is a vector (the sum of all vectors is the net force) force is the capacity to do work or cause physical change
How is force measured?
in Newtons (Force = mass x acceleration Newton = kg x m/s^2 A Newton is the amount of force require to move one kg of an object one meter per second squared)
What is the force of gravity?
Everything close to the earth’s surface will “fall” or accelerate at 9.81m/s^2 = gravitational force. (Gravitational force is also known as the weight of an object)
What is the difference between a Newton and a dyne?
- they both measure force - a dyne is 1/1000th of a Newton; it is used when very small forces are being measured
What is pressure?
Pressure is force dispersed over an area. F P = —- a (force is directly proportional to pressure. area is inversely proportional to pressure)
What is a vector and what is scalar?
vector = deals with magnitude and direction (velocity, acceleration, force, etc) scalar = quantity described by a single unit (mass, temperature, length, etc)
Do objects fall at the same rate in a vacuum?
yuppers
Do objects fall at the same rate in the atmosphere?
nope. (things like velocity, gas density, frontal area, and drag coefficient come into play in the atmosphere)
What are the pressure equivolents to 100kPa?
1 atm = 1 BAR = 760 mmHg = 760 torr = 1020 cm H20 = 14.7 lb/in^2
What is gauge pressure? What is absolute pressure?
Gauge pressure is zeroed at atmospheric pressure (760mmHg or 14.7psi). (When gauge pressure reads “0” it actually equals atmospheric pressure, 760mmHg. Example: Bourdon gauges. ) Absolute pressure is zeroed in a vacuum so when it reads “0” it truly means below atmospheric pressure at 0mmHg. (Absolute pressure is considered more precise because it does not change with atmospheric pressure/altitude change. Newer vaporizers use absolute pressure and do not require calibration with altitude change. Barometers measure absolute pressure)
What is Newton’s 1st Law of Motion?
An object will remain at rest or in motion indefinitely unless a net force acts upon the object.
What is Newton’s 2nd Law of Motion?
Force is proportional to a specific mass and an acceleration in a specific direction.
Which of these syringes would apply the most pressure if the same amount of force was applied to each? Which would have the least pressure?
the top one would have the least amount of pressure.
the bottom one would have the most pressure.
