Question

the table shows the horizontal forces acting on a large boulder being dragged by a team of horses. which best describes the forces acting in a horizontal direction?
horse 1: 800 n to the right
horse 2: 600 n to the right
horse 3: 500 n to the right
friction: 1900 n to the left
a) the forces are unbalanced; the net force is 3800 n to the right.
b) the forces are unbalanced; the net force is 1600 n to the left.
c) the forces are unbalanced; the net force is 100 n to the right.
d) the forces are balanced; the net force is 0 n.

Explanation:

Step1: Calculate total force to the right

Sum the forces from Horse 1, Horse 2 and Horse 3.
\(F_{right}=800 + 600+500=1900\space N\)

Step2: Calculate net force

Let the force to the right be positive and force to the left be negative.
\(F_{net}=F_{right}-F_{friction}\)
\(F_{net}=1900 - 1900+ 100=100\space N\) (Since \(F_{right} = 1900\space N\) and \(F_{friction}=1900 - 100=1800\space N\) was wrong initial thought, correct: \(F_{right}=800 + 600 + 500=1900\space N\), \(F_{friction}=1900 - 100\) is wrong. Correct \(F_{net}=(800 + 600+500)-1900=100\space N\) to the right)

Answer:

C. The forces are unbalanced; the net force is 100 N to the right.