1. The Kinematics Equations (1D Equations of Motion)
Unit 2 Class Notes
The Kinematics Equations (1D Equations of Motion)
Honors Physics

2. Day 6
Mixed Review (part II)

4. Dx = 2,224.5m
ttotal = m28.72 sec

6. Clearly this is a free-fall problem
Remember the free-fall assumptions:
V1 = 0, a = -9.8m/s2, down is negative
Solve the appropriate equations:
What must be neglected??? AIR RESISTANCE!!!

7. Again, this is a free-fall problem
Remember the free-fall assumptions:
V1 = 0, a = -9.8m/s2, down is negative
Solve the appropriate equations:
How far will it fall from 3-4 seconds?
During the 20th second?

8. Clearly this is a throw up problem
Remember the assumptions:
V2 = 0 top), a = -9.8m/s2, down is negative
Make sure to draw a picture and label the points appropriately. 2 3
What must be neglected??? AIR RESISTANCE!!! 4 1

9. Clearly this is a throw up problem
choose points 1 & 2
choose points 1 & 2
choose points 1 & 4
choose points 1 & 3
Clearly this is a throw up problem
Remember the assumptions:
V2 = 0 top), a = -9.8m/s2, down is negative
Make sure to draw a picture and label the points appropriately. 1 2 3 4
Choose two points, and work between these two points.

10. OR …. 2 3 Points 1-2 v1 = 10 m/s a = -9.8 m/s2 4 v2 = 0 m/s 1
Simply double the time from point 1 to point 2.
Dx = 0 m

11. Solve this quadratic equation for the times1 2 3 4
Points 1-3
v1 = 10 m/s
a = -9.8 m/s2
Dx = 5m
Solve this quadratic equation for the times
Graph y = -4.9x2 + 10x - 5
Hit “2nd Trace”, “ZERO”
It is 5 meters above the ground on the way UP and on the way DOWN.
Left Bound, Right Bound, Guess ….

12. Remember your assumptions, draw a picture, pick your points.1 2 3
Points 1-2
v1 = ?
a = ft/s2
x 1= 4 ft
x2 = 30 ft
v2 = 0
Dx = x2 – x1 = 26 ft
Points 1-3
a = ft/s2
x 1= 4 ft
x2 = 0 ft
v1 = ft/s
Dx = x2 – x1 = -4 ft

13. This is a chase problem!!!
x2N = x2O
But it’s also a CHALLENGING chase problem. Why? Because the “new” car undergoes two different motions (speeding up and then coasting).
Use the chase equation:
Notice how each different motion needs to be accounted for when writing the equation.

14. Plug in what you know How do we plug in for the times?
How do we find “a”?
tO = t (the total time)
v1 = 0
taccel = 40 sec (this was given)
v2 = 21 m/s
tcoast = t – 40 (the total time
minus the accel time)
t = 40 sec

15. Solve

16. THE GRAPHICAL APPROACH!!!13 21
v (m/s)
Time (sec) 40 t
THE GRAPHICAL APPROACH!!!
When the areas under the curves are equal, the new car has caught the older one.

17. TONIGHTS HW
NONE  ENJOY!!!