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[領域]力學

[題目]

      A 4kg cart starts up an incline with a speed of 3 m/s and comes to rest

2m up the incline. The total work done on the cart is ?

(a) 6 J (b) 8J (c) 12J (d)18J (e)not enough information given


[瓶頸]


我用機械能(力學能)守恆 : ΔUg = -ΔEk
                         ^^^^^^^^^^^^
                                  2
                          mgh = mv / 2

                          4*9.8*h = 4*9/2


這邊的h高度不知道T_T

所以選(e) 嗎？


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