Question

calculating net forces - examples
interpret each drawing of forces on the box. calculate and write the resulting net
force on the blank below the box (make sure to include the correct unit of
measure). on the next blank, write the word balanced or unbalanced and circle
the arrow for the direction of the resulting net force. see the examples below.
examples:
a.
225 n
net force
b.
75 n
net force
c.
50 n
100 n
50 n
net force
d.
792 n
400 n
632 n
900 n
100 n
net force
e.
550 n
1563 n
750 n
250 n
net force
f.
987,256 n
993,267 n
net force

Explanation:

Step1: Determine the formula for net force

When forces act in opposite directions, the net force \(F_{net}\) is \(F_{net}=|F_1 - F_2|\). When forces act in the same direction, \(F_{net}=F_1 + F_2\). If \(F_{net}=0\), the forces are balanced; if \(F_{net}
eq0\), the forces are unbalanced.

Step2: Solve for each case

• Case B:

There is only one force of \(75N\). So, \(F_{net}=75N\). Since \(F_{net}
eq0\), the forces are unbalanced.

• Case D:

Forces to the right: \(F_{right}=792 + 632+100=1524N\)
Forces to the left: \(F_{left}=400 + 900=1300N\)
\(F_{net}=|F_{right}-F_{left}|=|1524 - 1300|=224N\) (to the right). Since \(F_{net}
eq0\), the forces are unbalanced.

• Case E:

Forces to the right: \(F_{right}=550+750 + 250=1550N\)
Forces to the left: \(F_{left}=1563N\)
\(F_{net}=|F_{right}-F_{left}|=|1550 - 1563|=13N\) (to the left). Since \(F_{net}
eq0\), the forces are unbalanced.

• Case F:

Forces to the right: \(F_{right}=987256N\)
Forces to the left: \(F_{left}=993267N\)
\(F_{net}=|F_{right}-F_{left}|=|987256 - 993267|=6011N\) (to the left). Since \(F_{net}
eq0\), the forces are unbalanced.

Answer:

• B: Net Force \(75N\), unbalanced (circle the left - pointing arrow)
• D: Net Force \(224N\), unbalanced (circle the right - pointing arrow)
• E: Net Force \(13N\), unbalanced (circle the left - pointing arrow)
• F: Net Force \(6011N\), unbalanced (circle the left - pointing arrow)