1. Kinematics Flashcards
What are the following prefixes? pico nano mega giga
pico: 10e-12
nano: 10e-9
mega: 10e6
giga: 10e9
What is the equation for average velocity?
v = displacement / time
an average can also be taken as v = (vi + vf)/2
What is the average velocity of a blood cell traveling in a circuit?
Zero!
v = displacement / time
displacement is zero
t or f, the average speed is NOT the magnitude of the average velocity
true, for example, a runner runs at 5 m/s around a 50 m circle.
his average speed is 5m/s
but his velocity is 0 m/s
same would apply in a triangle (runners displacement is the hypoteneus but he runs the outer lines)
What is the formula for average acceleration?
a = change in velocity / time
If an objects velocity and acceleration are perpendicular, what is true?
if velocity and acceleration are perpendicular, then speed is constant
therefore an object can be accelerating if only its direction is changing.
What are the five formulas for uniform motion (constant acceleration)?
All uniform motion formulae can be derived from the velocity and acceleration formulas.
- d = 1/2(v + vi)t missing acceleration
- v = vi + at missing displacement
- d = vit + 1/2at^2 missing final velocity
- d = vt - 1/2at^2 missing initial velocity
- v^2 = vi^2 + 2ad missing time
Explain the slope and area under the curve of a velocity vs time graph.
The slope of a velocity vs time graph gives acceleration (change in velocity over time)
average velocity = d / t
d = vt
The AUC of a velocity vs time graph gives displacement.
what is g, the gravitational acceleration constant?
g = 9.8 m/s^2
What is projectile motion?
When an object is traveling in the x and y direction while experiencing the downward force of gravity.
to solve these questions, we split everything into x and y components (e.g. dx, vx, vix, etc).
Explain horizontal acceleration and velocity in projectile motion.
in the x-direction, acceleration is zero (it is not even changing directions).
no acceleration means velocity is constant in the x-direction.
therefore, vix = vx
Explain how you would solve for the range and height of a projectile in projectile motion.
range is dealing with the x component
d = vot + 1/2at^2
a in the x direction is zero, therefore
x = voxt
height is dealing with the y component
d = vot + 1/2at^2
a in the y-direction is -g
y = voyt + 1/2(-g)t^2
the big five kinematics equations can be manipulated to answer any free fall or projectile motion question.
What is true when a projectile has reached the apex of its path (the highest point)?
At this moment, its velocity is tangent (as always) to its path. Here, all of its velocity is in the x-direction, and its y-velocities magntiude is zero, pointing down.
How do you find the initial velocity in the x and y direction?
The projectile is launched at some angle to the horizon. Using this angle and the initial velocity, we can solve using SOHCAHTOA to find Vox and Voy.
Voy = sin(theda) Vo
Vox = cos(theda) Vo
