Acceleration 1D motion with Constant Acceleration Free Fall Lecture 04 (Chap. 2, Sec. 6-10 ) General...
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Acceleration 1D motion with Constant Acceleration Free Fall Lecture 04 (Chap. 2, Sec. 6-10 ) General Physics (PHYS101) ections 30 and 33 are canceled and became section 2
Acceleration 1D motion with Constant Acceleration Free Fall Lecture 04 (Chap. 2, Sec. 6-10 ) General Physics (PHYS101) Sections 30 and 33 are canceled
Acceleration 1D motion with Constant Acceleration Free Fall
Lecture 04 (Chap. 2, Sec. 6-10 ) General Physics (PHYS101) Sections
30 and 33 are canceled and became section 27
Slide 2
Lightning Review Displacement - change of position Average
velocity - displacement over time interval Instantaneous velocity -
the same but for very small time interval Last lecture:
Slide 3
Average Acceleration Average acceleration is the rate of change
of the velocity Changing velocity (non-uniform) means an
acceleration is present Average acceleration is a vector quantity
(i.e described by both magnitude and direction) SI unit: m/s 2
Slide 4
Instantaneous Acceleration Instantaneous acceleration is the
limiting case of the average acceleration as the time interval goes
to zero.
Slide 5
Graphical Interpretation of Acceleration Average acceleration
is the slope of the line connecting the initial and final
velocities on the velocity-time graph Instantaneous acceleration is
the slope of the tangent to the curve of the velocity-time graph
for the given value of time
Slide 6
1D motion: uniform velocity Uniform velocity (shown by red
arrows maintaining the same size) Acceleration equals zero
Slide 7
1D motion: constant (positive) acceleration Velocity and
acceleration are in the same direction Acceleration is uniform
(blue arrows maintain the same length) Velocity is increasing in
time (red arrows are getting longer)
Slide 8
1D motion: constant (negative) acceleration Velocity and
acceleration are in opposite directions Acceleration is uniform
(blue arrows maintain the same length) Velocity is decreasing (red
arrows are getting longer)
Slide 9
1D motion: constant acceleration Our job: to find the equation
for the position and velocity of the object to make
predictions!
Slide 10
10 1D motion with constant acceleration Recall that We know
that We find v t v0v0 Since x t x0x0
Slide 11
11 1D motion with constant acceleration
Slide 12
12 Summary of kinematic equations: 1D motion acceleration is
constant displacement as a function of velocity and time
displacement as a function of time velocity as a function of time
velocity as a function of displacement average velocity
Displacement as a function of velocity
Slide 13
13 Free fall - 1D motion with constant acceleration
Slide 14
14 Free fall - 1D motion with constant acceleration 0 x 1 2 3 0
y 1 2 3 All objects moving under the influence of only gravity are
said to be in free fall All objects falling near the earths surface
fall with a constant acceleration This acceleration is called
gravitations acceleration, indicated by g and always points
perpendicular to the earths surface y
Slide 15
15 acceleration displacement vs velocity and time displacement
vs time velocity vs time velocity vs displacement average velocity
displacement vs velocity Free fall - 1D motion with constant
acceleration
Slide 16
16 Case 1: zero initial velocity y
Slide 17
17 Case 2: NONzero initial velocity y y Case 1 Case 2
Slide 18
18 Case 3: object thrown upward
Slide 19
19 Case 4: object thrown upward
Slide 20
Free fall Mass does not matter, if the air resistance is
neglected
Slide 21
21 Positive acceleration
Slide 22
22 Negative acceleration
Slide 23
23 1D motion with constant acceleration Example 1: A car is
traveling with a constant speed v 0. At some time, the driver puts
on the brakes, which slows the car down at a rate of a. Find: how
much farther does the car travel for time t f, before it stops
completely. low long does it travel if the stopping distance is x
f. Given: v 0 =v 0 a=-a x 0 =0 t 0 =0 v=0 Find: 1) x f =?, knowing
t f. 2) t f =?, knowing x f.