Space Time & Motion A.2 Forces & Momentum (id: 4babc876b)

本题目来源于试卷: Space Time & Motion A.2 Forces & Momentum，类别为 IB物理学

[单选题]
A 74 kg boy starts to ride a 6.0 kg bic+bclyj1sjx10yhj 5sg0 tm. t3 ycle from rest. The graphyts2q g bib, n oa+a 9rsxyuzi.o6 n*1b5w8g-) shows how the acceleration a of the bicycle varies with a2s rby9b.osg,i1 xa5n+wq goz -)yunit8 *b6the distance travelled x

What is the total work done by the boy?

A. 0.3kj
B. 3.7kj
C. 4.0kj
D. 6.0kj


参考答案:  C


本题详细解析:

$\underline{\text{Explanation}}$: 
Work Done = (Force $\times$ Distance) = (Mass $\times$ Acceleration $\times$ Distance)

(Acceleration $\times$ Distance) is the area under the graph.

Work done is (Mass $\times$ Graph Area) = (74+6)(50) = 4000 J = 4 kJ

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