∙ physics is shown through math and is about the properties of natural objects ∙ try to predict what will happen through a physical (empirical) law which has a range of validity
∙ must include units with everything
o in mechanics you only need length, time, and mass these are known as base quantities and all other units can be derived from these
∙ need to use dimensional analysis (series of multiplying fractions) to convert units the units you have should cancel so that you get the units you want
∙ must maintain sigfigs, least number for multiplication and division, smallest decimal place for addition and subtraction
∙ parameters that can be completely described by a number is a scalar (ex: temperature, mass, speed)
∙ parameters that require information about both magnitude and direction are known as vectors (ex: displacement, velocity, acceleration) Don't forget about the age old question of What is the function of the simple columnar epithelium?
∙ displacement shows the distance from point a to point b and is the same no matter how much distance was traveled to get there
∙ to show a vector you either have the letter in bold or the letter with an arrow over it, the magnitude of the vector is indicated by italic print
∙ vectors along the x, y, and z axes are labeled by i, j, and k with a ^ over each ∙ vector notation
∙ use these to find the x and y components of the vector if the x and y components are known you can use these formulas to find the magnitude and the angle
of the vector
∙ to add vectors you need to add each of the components (order doesn’t matter) to subtract vectors you need to subtract the components (order does matter)
∙ to multiply a vector by a scalar you have to multiply each component by that scalar value ∙ the scalar product (dot product) of two vectors use this if you know the magnitude and of We also discuss several other topics like What are passive leg exercises?
the vectors and the angle between them Use this when you only
know the components
∙ for the vector product (cross product) of two vectors, you can use this if you know the We also discuss several other topics like What were some of the characteristics of paleolithic society?
magnitude of the vectors and the angle between the two vectors the order matters and if you switch the order you must negate the first term after it has been switched. this only gives you the magnitude. you need to use the right hand rule to find the direction.
o the right hand rule:
put your right hand so that it goes along the first vector and so that you can fold your fingers to line up with the second vector and form a right angle. your thumb then points in the direction of the third vector
Don't forget about the age old question of How does the criminal justice system respond to crime?
o the magnitude can also me found using
∙ Mechanics is composed of kinematics and dynamics
o kinematics is how to describe motion
o dynamics is what the origin of motion is
∙ the negative sign indicates direction along the straight line path
∙ a change in position is shown through
∙ the average velocity is shown by
∙ the average speed is the total distance traveled in a time interval, average speed is a scalar
unit, not a vector
∙ instantaneous velocity is shown by the slope of the tangent line of the position versus time graph and
∙ average acceleration is
∙ instantaneous acceleration is the slope of the tangent line of the velocity versus time graph
∙ the relationship of the graphs to each other
∙ equations for motion with constant acceleration ∙ for one dimensional kinematics problems you should draw a picture and label the axes and the vectors If you want to learn more check out How are strands connected?
We also discuss several other topics like What does the thermodynamic variable mean?
∙ the force of gravity is 9.8 m/s^2
∙ for projectiles:
o the time it takes to reach the height is
o the height it reaches is
∙ for nonconstant acceleration you can find the velocity by
∙ you can find the displacement by