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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