Question

CAN SOMEONE HELP PLZ
the velocity of an object fired directly upwards given v=96-48t, where t is in seconds. When will the velocity be between 48 and 80 feet per second??

Answer 1

Treat this like 2 separate problems.

1) Find the time at which the vel. is 48 ft/sec:
      
           v = v0 + at   is given here and is v = 96-48t            (feet/sec)
            
           Set this equal to 48:  48 = 96 - 48t.  Divide all terms by 48:

                                               1=2-t   =  t = 1 sec

2) find the time at which v = 80 ft/sec:

80 = 96-48t     =>    48t = 16, so t =1/3 sec, or   t= 0.33333 ... sec (approx.)


When will the velocity be between 48 and 80 feet per second?  Between t=13 sec and  t=1 sec (answer)