LECTURE #6 - linear kinematics (2) Flashcards
what are kinematics ?
describes ,motion in regards to the position, velocity, and acceleration of object without considering the forces causing motion
what is distance ?
length of a path followed by object from initial to final position
TRUE OR FALSE
distance is necessarily a straight line
FALSE
not necessarily a straight line
what is scalar quantity ?
one magnitude
length of path is described by what term ?
distance
what is displacement ?
straight line distance in a specific direction from initial to final position
“as the crow flies” is used for what term ?
displacement
what is the formula for displacement ?
displacement = position (final) - position (initial)
TRUE OR FALSE
distance and displacement = the same thing ?
FALSE
distance doesn’t = displacement
which line in a graph is displacement ?
the straight line from the initial to the final
TRUE OR FALE
think of resultant as the displacement
TRUE
how do we calculate displacement :
x1,y1 & x2,y2 is resultant
- use SOHCAHTOA (in this case tan) and solve the missing sides
0 used pythagorean theorem
what sport did we discuss displacement for ?
tennis
describe some points based of the tennis video :
- no more line judges
- evolution in business and the sport of tennis
- cost expensive
- clear application that influences tennis
what is speed ?
rate of motion
how to calculate speed ?
Δ displacement / Δ time
TRUE OR FALSE
scalar quantity is magnitude only
TRUE
what term is used for how long it takes to accomplish a rate of motion/speed/movement ?
time
what is velocity ?
displacement of an object over time
what is the formula for velocity (v) ?
v = Δ displacement / Δ time
TRUE OR FALSE
the friction of velocity (v) is negative or positive
TRUE
TRUE OR FALSE
direction of motion influences velocity direction
TRUE
what formula is used to find the resultant ?
pythagorean theory
what are the two methods of instantaneous velocity ?
- central difference method
- tangent
what does it mean when velocity is positive ?
- going upwards
- gain in position
what does it mean when velocity is straight line ?
- vertical velocity is 0
- constant
what does it mean when velocity is negative ?
- going downwards
- lose in position
TRUE OR FALSE
rate of change in velocity is a vector quantity (acceleration)
TRUE
TRUE OR FALSE
acceleration occurs if velocity magnitude or direction changes
TRUE
what are the three types of acceleration ?
positive negative and zero
what does positive acceleration mean ?
gaining velocity
what does negative acceleration mean ?
losing velocity
what does zero acceleration mean ?
means @ that point you’re at a constant role (it’s remaining constant)
is someone described as being “quick” or having “good acceleration” the same as being fast ?
- No !
- acceleration describes a persons ability to change speed or direction (not top speed)
is a 400m runner that is running at a constant speed around a track accelerating ?
yes & no
on the straights we are not accelerating because there is no change in direction, but around the curved we are changing directions therefore ac celebration has occurred
average vs instantaneous …
what is average ?
- value over an interval or time
- do not represent max values
average vs instantaneous …
what is instantaneous ?
- value at a given moment in time
- may represent max values
- approach instantaneous measures with small time intervals
what odes magnitude of instantaneous velocity = ?
instantaneous see
when do we usually see max velocity ?
@ around 2/3
when do we see max acceleration ?
@ beginning
what is the formula for acceleration ?
velocity / time
