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The answer isn't -9.9452 !

 

A 1210 kg roller coaster car is moving 7.33 m/s. As it approaches the station, brakes slow it down to 1.88 m/s over a distance of 5.29 m. How much work did the breaks do?

 

Fdcos(theta)

 Dec 9, 2016

Best Answer 

 #1
avatar+37084 
+5

The work done on an object by a net force equals the change in kinetic energy of the object:

1/2mv^2   originally was    (1/2)  1210 (7.33)^2    = 32505.98 j

                 later was           (1/2)  1210 (1.88)^2   =    2138.31  j   

 

Work = KEf - KEo  = work done = -30367.67 j

 Dec 9, 2016
edited by ElectricPavlov  Dec 9, 2016
 #1
avatar+37084 
+5
Best Answer

The work done on an object by a net force equals the change in kinetic energy of the object:

1/2mv^2   originally was    (1/2)  1210 (7.33)^2    = 32505.98 j

                 later was           (1/2)  1210 (1.88)^2   =    2138.31  j   

 

Work = KEf - KEo  = work done = -30367.67 j

ElectricPavlov Dec 9, 2016
edited by ElectricPavlov  Dec 9, 2016
 #2
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0

I've tried that and my program isn't accepting it as the answer to the question.

 Dec 9, 2016

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