[单选题]
A 74 kg boy starts to ride a 6.0 kg bicycle from rest. The graph s
m4h+mrs7din ee cx0.0hows ho
2rp 9nb kn5-+igcsw(i. x3imqw the acceleration a of the bicycle varies with the distance
+39 km(2iniwrq-5pcs.bnig x 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:
Explanation:
Work Done = (Force × Distance) = (Mass × Acceleration × Distance)
(Acceleration × Distance) is the area under the graph.
Work done is (Mass × Graph Area) = (74+6)(50) = 4000 J = 4 kJ