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A train slows from a speed of 40 m/sec to a speed of 30 m/sec in 1500 m. What is its acceleration?

I tried to solve this but I can't get the right formula >.<

 Sep 20, 2018
 #1
avatar+128079 
+1

I'm not a Physics expert, but  I believe we need this equation, RP

 

VF^2  =VI^2  + 2 * a * d

 

VF  = 30m/s

VI = 40m/s

d  = the displacement  [ how far it moves]....so we have

a = acceleration  (in m/s^2) = ???

 

30^2  = 40^2  + 2 * a (1500)

 

900  =  1600 + 3000a    subtract 1600 from both sides

 

-700  = 3000a     divide  both sides by  3000

 

-700 / 3000  = a   = -7/30 m/s^2 ≈ -0.233 m/s^2  [ this makes sense....we are  decelerating !!! ]

 

 

cool cool cool

 Sep 20, 2018
 #2
avatar+2448 
+1

Thank you so much!!

RainbowPanda  Sep 20, 2018

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