2. Chapter 2 Uniformly Accelerated Motion

3. ACCELERATION is the final velocity is the initial velocity
is the time to change velocity
Units – m/s2, ft/s2, etc.

4. For the acceleration tangent to the path of motion

5. UNIFORMLY ACCELERATED MOTION ALONG A STRAIGHT LINE
This is constant acceleration in a straight line.
The vector nature can be specified with + and - signs.

7. These equations are all you need to work most
uniform accelerated motion problems.

8. DIRECTION IS IMPORTANT
Choose a positive direction and a negative direction.

9. GRAPHICAL INTERPRETATIONS
A distance versus time curve always has a positive slope.
A displacement versus time curve is not that restrictive.
The slope on a displacement versus time curve is
the instantaneous velocity.
The slope on a velocity versus time curve is
the instantaneous acceleration.

10. Consider the function Plotted x(m) t(s) v(m/s) t(s) a(m/s2) t(s) 16 3216 32
t(s) 2 4 6
v(m/s) 12
-12
-24
-36 2 4 6
t(s)
a(m/s2) 12
-12
-24 2 4 6
t(s)

11. ACCELERATION DUE TO GRAVITY (g)
The acceleration due to gravity is down and equals

12. VELOCITY COMPONENTS Consider projectile motion. q
Speed is always positive,
however, velocity components have direction.

13. PROJECTILE PROBLEMS Consider projectile motion with no air resistance.
Simply consider two motions:
Horizontal motion is constant speed
Vertical motion is constant accelerated motion.
Useful equations are:

14. Remember that

15. Supplementary Problem 2.22
For the object whose motion is plotted in Fig. 2-2, find its instantaneous velocity at the following times: (a) 1.0 s, (b) 4.0 s, and (c) 10 s.

16. 14 12 10 8
Displacement along the y-axis (m) 6 4 2 5 10 15
Time (s)

17. 14 12 10 8
Displacement along the y-axis (m) 6 4 2 5 10 15
Time (s)

18. 14 12 10 8
Displacement along the y-axis (m) 6 4 2 5 10 15
Time (s)