Chapter 2 Uniformly Accelerated Motion

2. Chapter 2Uniformly 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. 32 16 0 6 2 4 12 0 4 6 2 -12 -24 -36 12 4 6 2 0 -12 -24 Plotted Consider the function x(m) t(s) v(m/s) t(s) a(m/s2) 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 0 10 15 0 5 Time (s)

17. 14 12 10 8 Displacement along the y-axis (m) 6 4 2 0 10 15 0 5 Time (s)

18. 14 12 10 8 Displacement along the y-axis (m) 6 4 2 0 10 15 0 5 Time (s)