Introduction Flashcards
What are base quantities?
The 7 fundamental quantities of the SI
What is a versor?
A vector that has a magnitude equal to 1
What happens when you multiply a vector with a scalar?
It acts only on the magnitude, if it is negative the direction is changed
4 types of motion
Uniform linear motion
Uniform accelerated linear motion
Uniform circular motion
Harmonic motion
How do you change degrees to raidens?
Multiply by pi/180
What does Bernoulli’s equation describe?
The behaviour of an incompressible fluid along a streamline
Relating the fluid velocity, elevation and pressure along that streamline
What are observed objects?
Physical quantities
What is quantification method?
Measurement
What is measure?
The comparison between two homogeneous quantities
How do you change celcius to Kelvin?
+273
Formula for work
L=Fs=Fs*cos(theta)
What is the dot product of vectors?
Commutative, not associative (scalar product between two vectors generates a scalar)
What is the cross product of two vectors?
A vector
Formula for cross product between two vectors?
C=a^b=aBsine(theta)
What does the mixed product between vectors contain?
Both a scalar and a vector
Different name for classical mechanics
Newtonian mechanics
What causes a car to turn in uniform circular motion?
Centripetal force
When a car turns is it inertial?
No
Are objects inside a car turning inertial?
Yes
What is mass?
A constant that is always positive
1N=?
Kg*m/s^2
Relative density=?
m/m’
mass/mass of equal volume distilled water at 4c
Absolute density=?
m/V
Relative specific weight=?
p/p’
weight/weight of equal volume of distilled water at 4c
Absolute specific weight=?
p/V=(m/V)g=absolute densityg
Ratio between weight and volume
What is torque measured in?
Netwon*meter
Same as measurement of joule
What is moment of force?
Torque
Moment(M)=?
r*F
What is momentum denoted by?
q
q=?
m*V
What does the principle of conservation of momentum state?
That in an isolated system the momentum is conserved
m1v1+m2v2=?
0
Conservation of momentum
Why is the recoil of earth when a man jumps infinitely small?
Because the mass og the earth is infinitely greater than the man’s
Force of gravity=
G* (m1*m2)/r^2
G= gravitational constant
What law is elastic force?
Hooke’s law
Hooke’s law=?
F=?
-k*x
k is a constant
x is body deformation
Reaction of body is directly proportional to the undergone deformation with an opposite direction
Which law describes electrostatic force?
Coulomb’s law
Electrostatic force=?
F=?
K* (q1q2)/r^2
q are the charges
K is constant (910^9)
What is uniform circular motion?
The motion of a material point that moves on a circumference with a constant tangential velocity
What changes from point to point in uniform circular motion?
The direction of the velocity (which is tangent to the trajectory)
Centripetal acceleration=?
ac=?
v^2/r
What is a restoring force (shm)?
Acceleration directed towards the center of oscillation and proportional to the distance
When is a force doing work?
When it acts on a body so that there is a displacement of the point of application in the direction of the force
Symbol for work
L
L=?
(Work)
Fs=Fs*cos(theta)
If the angle of work is acute what kind of work is it?
Positive (motor)
If the angle of work is obtuse what kind of work is it?
Negative (resistant)
If the angle of work is right what kind of work is it?
None, L=0
What is the SI unit of work?
Joule
What are 2 practical units of work?
Electronvolt (eV)
Kilogram-meter
5 forms of energy
Kinetic
Gravitational
Electric potential
Thermal
Chemical
What are work and energy in relation to each other? and what does that imply?
They are homogenous quantities which means they have the same unit of measurement
Formula for kinetic energy (Ec)
Ec=1/2mv^2
What is the variation of the body’s kinetic energy equal to?
The work done by the force F that set it in motion
What does work indicate?
A transfer of energy from one form to another
What is a force field?
Area of space where a force acts in each point
What are the forces and fields defined as if the nature of the forces is such that work doesn’t depend on the trajectory?
Conservative
What is the work done along a closed trajectory if the forces are conservative?
=0
W=?
(work done on object)
Change in kinetic energy
What is the change in kinetic energy in a conservative field?
Zero as the work done is also zero
What is the work done along a closed trajectory in dissipative forces?
Not null, the work depends on the path taken from start to end point
What is potenital energy denoted by?
U
Formula for gravitational potential energy
U=mgh
Is the kinetic energy theorem valid for both the conservative and non-conservative forces?
Yes
What happens to the sum of the kinetic and potential energy when only conservative forces act on a body?
They remain constant
Formula for principle of conservation of mechanical energy
U+Ek=constant
P=?
L/^t=E/^t=F(^s/^t)=Fv
SI unit of measurement for power
Watt=joule/s
A practice unit of measurement for power
horsepower (hp)
What is Kleiber’s law?
Empirical relationship between metabolic rate and mass of an organism
What is the absorbed power which measures the speed of energy consumption in physiology called?
Metabolism
What is the yield of the human body?
15-20% (most absorbed energy is dissipated as heat)
Ec=?
F*s
