Position and Movement Question 3

3) A sports car accelerats from 60km/h to 90hm/h in 5s and then from 90km/h to 120km/h in a further 7s . What is the average acceleration of the sports can ?

A 5ms-2 , B 2.78ms-2 , C 1.43ms-2 , D 1.39ms-2 , Ans = D

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  • 1 十年前
    最愛解答

    change 60km/h into ms-1

    60 X 1000/3600 = 16.67

    90 x 1000/3600 = 25

    120 x 1000/3600 = 33.33

    The quesiton ask for the average acceleration fo the sports car,

    therefore it is a = initial and final / time taken

    33.33 - 16.67 / (5+7) = 1.39ms-2

    therefore the ans is D

    資料來源: me
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