Question

1. a book is at rest on a tabletop. all forces are balanced.

calculate the missing forces in the following free body diagrams.

Explanation:

Step1: Analyze the first free - body diagram (for the first box)

In the vertical direction, the sum of forces \(F_{nety}=0\). Let the force at \(A\) be \(F_A\). We know that \(F_{nety}=F_A + 50-200=0\).

$$F_A=200 - 50$$

Step2: Analyze the second free - body diagram (for the second box)

In the vertical direction, \(F_{nety}=F_C-200 = 900\).

$$F_C=900 + 200$$

Step3: Analyze the third free - body diagram (for the third box)

In the vertical direction, \(F_{nety}=0\), so \(F_D = 300\). In the horizontal direction, \(F_{netx}=F_E-90=60\).

$$F_E=60 + 90$$

Step4: Analyze the fourth free - body diagram (for the fourth box)

In the vertical direction, \(F_{nety}=F_F-20=0\). In the horizontal direction, \(F_{netx}=G - H=50\). Let \(H = 0\) (assuming no other horizontal forces mentioned for simplicity in the absence of more data, and if we consider only the given \(F_{netx}\) and \(G\) relation), then \(G = 50\).

Answer:

• \(F_A = 150\space N\)
• \(F_C=1100\space N\)
• \(F_D = 300\space N\), \(F_E = 150\space N\)
• \(F_F=20\space N\), \(G = 50\space N\)