Question

what is the magnitude (size) of the missing force in the figure diagrammed below?
hint: when using the ( f = ma ) formula, ( f ) is net force.
answer: 10 choose your answer... choose your answer... ( m/s2 ) ( kg ) ( n )

Explanation:

Step1: Calculate the net force

According to Newton's second law \(F = ma\). Given \(m = 5\space kg\) and \(a=4\space m/sec^{2}\), then \(F_{net}=ma\).

$$F_{net}=5\times4 = 20\space N$$

Step2: Set up the equation for the net force

Let the missing force be \(x\). The forces acting on the object: to the right we have \(18 + 12\), and to the left we have \(x\). The net force \(F_{net}=(18 + 12)-x\)
Since \(F_{net}=20\space N\), we have the equation \(20=(18 + 12)-x\)

Step3: Solve for \(x\)

First, simplify the right - hand side of the equation: \(18+12 = 30\). So the equation becomes \(20 = 30-x\)
Add \(x\) to both sides: \(20+x=30\)
Subtract \(20\) from both sides: \(x = 30 - 20\)

$$x = 10\space N$$

Answer:

\(10\space N\)