Given data:
* The mass of the child is 40kg.
* The reading of the scale is 30 N.
Solution:
(a). The free body diagram of the given system is,
(b). The weight of the child is,
[tex]\begin{gathered} W=40\times9.8 \\ W=392\text{ N} \end{gathered}[/tex]The Scale reading is,
[tex]N=30\text{ Newton}[/tex]The net force acting on the box in terms of the weight of the box is,
[tex]\begin{gathered} F_{\text{net}}=N-mg \\ F_{\text{net}}=30-392 \\ F_{\text{net}}=-362\text{ N} \end{gathered}[/tex]According to the Newton's second law,
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