Respostas

2013-04-17T11:36:59-03:00

v=15+20t

v=v_o+at

 

Comparando:

 

v_o=15

 

a=20

  ---------------------------  

v=15+20t  

 

v=15+20.(4)  

 

\boxed{v=95m/s}

  -----------------------------  

v=15+20t  

 

215=15+20t  

 

\boxed{t=10s}

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2013-04-17T11:52:25-03:00

a) V=15+20t = 15 + 20 . 0 = 15 m/s 

 

b) V=15+20t = 15 + 20 . 4 = 15 + 80 = 95 m/s 

 

c) V=15+20t => 215 = 15 + 20t = 200 = 20t => 20t = 200 => t = 200/20 => t = 10 s

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