lecture 1 chem/physics Flashcards
(39 cards)
causes of motion
newtons 3 laws
Newton’s first law, give an example
Object at rest or moving at a constant speed in a straight line and will continue in that state until external force acts on it
Example-bicycle straight road with cyclist moving with constant velocity and rides through puddle-causes bike to slow or stop
Newton’s 2nd law
How does this explain Newtons 1st law
Give example
force=massxacceleration (F=ma)
-Acceleration and force are vectors
-Direction of force vector and acceleration vector equal
Quantitative explanation of newton’s first law
-Example-push harder to get a big object moving (obese person on a stretcher)
Newton’s 3rd Law
Give example
for every action, there is an equal and opposite reaction
example-gravity
What is mass?
Mass is amount of matter in an object
Define weight
Weight is gravitational force exerted on an object by a much larger object
Mass verses weight example
Example-on earth and the moon I have the same mass, but I weigh less on the moon because gravity on the moon is less
mass equation
M=f/a
Velocity
Velocity-displacement of object/time to make the trip
(Change in position, motion) How position changes with time
Speed-what type of value
-what does speed involve?
- Speed is a scalar value, does not specify direction of motion
- Speed involves distance, velocity involves displacement
distance-is it positive negative or 0
always positive
displacement-is it positive, negative or 0
can be positive, negative, or 0
velocity example
Example-in a 500 mile car race, a car travels 250 times around a 2 mile oval track in 3 hours, the speed is 500 miles/3hours=167 miles, but the velocity is 0mph because care returns to exactly where it started
vectors
Vectors have magnitude and direction (units, direction of vector) example-weight, velocity
scalar quantities
magnitude only, needs associated units (distance, height, mass age, etc.)
adding vectors-what does length represent
how is direction denoted
what do head and tail mean
give example
Length represents size and magnitude, and direction of arrow denotes direction
-End of arrow is the head, tip direction
Example-if you are walking 5 miles east and a train is traveling 30 miles east, the magnitude is 35 miles, and the direction is east
acceleration formula
Acceleration=change in velocity/change in time
Can change acceleration by changing speed, direction, or both
-Describes how velocity changes over time
-Newton’s 2nd law-force=massxacceleration-puts the “thrill in a thrill ride”
*not just speeding up, but describes how velocity changes over time
-Example-ball thrown up in air, velocity gets smaller as time gets bigger (ball slows and stops, then changes direction)
-Velocity of ball when it returns to starting point equal to magnitude of initial velocity→gravity, projectile motion=acceleration due to gravity=9.8m/s2 downward
acceleration-which newton law
Newton’s 2nd law-force=massxacceleration-puts the “thrill in a thrill ride”
how can you change acceleration and is it a vector
- Can change acceleration by changing speed, direction, or both
- Acceleration is a vector quantity so changing direction also changes acceleration
force equation
f=massxacceleration (newtons 2nd law)
force-which newtons law
newtons 2nd law f=massxacceleration
force-doubling the diameter of an syringe increases or decreases pressure? by a factor of what?
what is force
syringe example-3ml verses 10ml syringe-which has more pressure
Force=a push or a pull-example pushing a plunger on a syringe
Doubling diameter of syringe decreases pressure by a factor of 4
-Force related to mass-newton’s 2nd law (force=massxacceleration)
If you squirt a 3ml syringe with a 19-gauge needle across the room verses a 10ml syringe with a 19-gauge needle across the room, more pressure from 3ml syringe
force in relation to acceleration
-Force required to produce acceleration, the larger the force, and the larger the acceleration
gravity-which Newton law?
newtons 3rd law-every action has an equal and opposite reaction
