Chapter 4, Problem 8STP

To determine

To Choose: The correct option.

Answer to Problem 8STP

Correct option is (B).

Explanation of Solution

Given:

Mass of the child, $M=45\text{ kg}$

Mass of the tire, $M=3.2\text{ kg}$

Tension in the rope, $T=220\text{N}$

Gravitational acceleration, $g=9.8{\text{m/s}}^2$

Formula used:

  $F_{net}=mg-T$

Where,

  $m$ is the total mass

  $g$ is the gravitational acceleration

  $T$ is the tension

Calculation:

Total mass of the system is:

  $\begin{array}{l}M\text{'}=M+m\\ M\text{'}=45+3.2\\ M\text{'}=48.2\text{kg}\end{array}$

Net force can be calculated as:

  $\begin{array}{l}{F}_{net}=M\text{'}g-T\\ F_{net}=48.2\times 9.8-220\\ F_{net}=252.36\text{N}\\ F_{net}=2.52\times {10}^2\text{N}\end{array}$

Conclusion:

The value of the normal force being exerted on the child’s feet is $F_{net}=252.36\text{N}$