physics 1 Flashcards
What is the difference between vectors and scalars?
vectors - direction and magnitude
scalars- only magnitude
Is mass a scalar or vector?
scalar
Is momentum scalar or vector?
vector
When finding the x and y components of vectors, what formula should you use?
x-component- Vcos(theta) - use angle based on x-axis
y-component - Vsin(theta)
What is force?
Any influence capable of causing a mass to accelerate
What is the law of inertia?
objects in motion stay in motion, objects at rest stay at rest
What is mass in terms of inertia?
An objects mass is a measure of its inertia
What is the center of mass?
a weighted avg. of mass distribution
How do you find the center of mass of multiple objects?
Cmass= (r1m1 + r2m2 + r3m3) /mass of total
r- displacement vector between reference pt and each mass
difference between center of gravity and center of buoyancy
gravity - middle of mass
buoyancy - center of mass of the fluid displaced by the submerged object
What formula is Newton’s 2nd law?
Fnet = ma
What does Newton’s third law state?
when one object exerts force on a second object, the second object always exerts an equal and opposite force on the first object
difference between distance and displacement
distance - any length of travel
displacement - vector indicating position change from start to end, magnitude of displacement is shortest distance from start to finish
difference between speed and velocity
speed - rate of change in distance
velocity - rate of change of displacement
When you see “constant velocity”, what should you think?
no acceleration no net force no change in direction all forces sum to zero object is in equilibrium
Acceleration is any change in ___
velocity
If a ball is going up, it loses __ m/s of velocity each second
10
If a ball is falling, it __ velocity at __ m/s each sec
gains 10
How do you find avg velocity?
avg. velocity = initial velocity + final velocity/ 2
How do you calculate distance?
distance= rate x time
If a projectile has an initial vertical velocity of 30m/s, how long will it be in the air, how high will it go, and what will be its avg velocity during the entire trip?
6 seconds in air, 45 m, avg. 15 m/s
What is range?
horizontal distance traveled
How do you calculate range?
range = velocity in x-direction x time
Formula for calculating intitial or final velocity (assuming that you are throwing an object)?
V= square root (2gh) or V= square root (2ax)
greater cross-sectional area= __ air resistance
more
increased velocity = ___ air resistance
more
What is the formula for the universal law of gravitation?
F = Gm1m2/r(squared)
How do you calculate gravitational potential energy?
PE= mgh
How do you calculate gravitational potential energy in space, not assuming g=10 m/s?
PE = -Gm1m2/r
What is the cause of friction on a molecular level? microscopic level?
molecular - electron clouds repel each other
microscopic - surfaces collide with each other
If there’s sliding it’s ___ friction
kinetic
If there is no sliding , it’s __ friction
static
What is the formula for friction force?
F= usFn or F= Usmgcos(theta)
formula for the force down an inclined plane?
F= mgcos(theta)
formula for normal force on an inclined plane
Fn= mgcos(theta)
Formula for the velocity of a particle at the base of an inclined plane
V= sq. root(2gh)
formula for acceleration down an inclined plane
a= mgsin(theta)
What is tension?
the force in a rope, string, cable
What is the tension in a rope being pulled from opposite ends with identical forces of 50 N?
50 N
What is Hooke’s Law?
F= k(delta)x
A student hangs a 4kg mass on a spring and it stretches 1 m. What is the spring constant, and how far will the spring stretch if he attaches a 2 kg mass?
40 N/m , 1/2 m
What is elastic potential energy?
The potential energy stored in a compressed spring
PE = (1/2)k(delta)x(sq
When is the potential energy of a pendulum at its maximum?
at the maximum height of the pendulum
When is the minimum potential energy of a pendulum?
at the bottom of the arc
What is simple harmonic motion?
anything that oscillates back and forth, represented by a sin wave graphically
frequency is the inverse of a __
period
What is the formula for the period of a pendulum?
T= 2pi(sq root)(L/g)
What is the formula for density?
D= m/v
What is specific gravity?
a ratio that describes how dense something is compared to water
What is the formula for specific gravity?
Density of substance / density of water
For objects floating in liquids, the fraction of the object __ = the ratio of the density of the __ to the density of the __
submerged, object, liquid
What is Archimedes’ principle?
If an objected is submerged in fluid, than the amount of fluid displaced is equal to the volume of the object
What is the formula for buoyant force?
F= pvg (v- volume of fluid displaced, p - density of fluid)
How does buoyant force change with depth?
It does not change with depth
What is the formula for apparent weight?
Apparent weight = actual weight - buoyant force
What is the formula for pressure?
P= F/A
What is atmospheric pressure?
the fluid pressure due to the earth’s atmosphere at
What is fluid pressure?
the force per unit area at some point within a fluid
What is gauge pressure?
the amount of pressure in excess of the ambient atmospheric pressure
What is absolute pressure?
actual total pressure of the atmosphere, plus gauge pressure
how many pascals equal 1 atm? How many mmHg? How many Torr?
1 x 10^5 pascals , 760 mmHg, 760 Torr
What is the fluid pressure formula?
P= pgh
p= density
What is Pascal’s Law?
Pressure is transmitted in all directions, undiminished, through a contained, incompressible fluid
What is ideal , non-viscous flow?
no friction between fluid and walls of pipe or within molecules themselves
What is Poiseuille flow?
how real, viscous fluids flow
What is laminar flow?
Fluid flows in pipes in concentric sheets, each with different velocities. fastest flow is in center of pipe and slowest at the sides
What is turbulence?
net flow is in one direction, there are random eddies, changes in direction, changes in velocity
What is the formula for flow rate?
Q = AV (A- always cross sectional area)
cardiac output =
stroke volume x heart rate
What is Bernoulli’s equation?
K= P + pgh + (1/2)pv^2
h- height P- pressure energy
If fluid velocity increases, pressure __
decreases
What are cohesive forces? Adhesive forces?
intermolecular forces between the molecules of a liquid, intermolecular forces between molecules of liquid and container
