12

  12–58. A two-stage rocket is fired vertically from rest with the acceleration shown. After 15 s the first stage A burns out and the second stage B ignites. Plot the v–t and s–t graphs which describe the motion of the second stage for 0 … t … 40 s.

12–62. If  the  position  of  a  particle  is  defined  as  s   = (5t - 3t2) ft, where t is in seconds, construct the s–t, v–t, and a–t graphs for 0 … t … 10 s.

 

12–63. From experimental data, the motion of a jet plane while traveling along a runway is defined by the v–t graph. Construct  the  s–t  and  a–t  graphs  for  the  motion. When t = 0, s = 0.

 

 

 

a (m/s2)

 

B

 

 

 

     A

 

 

 

20

 

15                                                                                                    v (m/s)

 

 

 

60

 

 

 

15                        40

 

 

 

Prob. 12–58

 

 

 

t (s)

 

 

 

 

 

20

 

 

 

 

 

5                           20                 30

 

t (s)