Question

Hello, I am currently trying to understand the concepts of tension force, could I have some help on this question?

Answer 1

Given that the maximum tension the wire can bear is 450 N.

The mass of one brick is m = 8kg

Two forces will act on the brick, one due to gravity i.e. mg, and the other due to tension in the wire.

The free-body diagram will be

Brick 2 experiences a force due to gravity downwards m2g and a tension T2

`\begin{gathered} T_2-m_2g=0 \\ T_2=m_2g \end{gathered}`

Brick 1 experiences a force due to gravity downwards m1g and a tension T1

`\begin{gathered} T_1-m_2g_{}-m_1g=0 \\ T_1=m_2g+m_1g \\ =(m_1+m_2)g_{} \end{gathered}`

Given that the maximum tension the wire can bear is 450 N.

The mass of one brick is m = 8kg

We have to calculate the force due to one brick.

The force due to gravity on one brick will be mg.

Here, g =9.8 m/s^2 is the acceleration due to gravity.

The force due to gravity on one brick is

`\begin{gathered} mg\text{ =8}*9.8 \\ =78.4\text{ N} \end{gathered}`

(a) The number of whole bricks that can be hung is

`\begin{gathered} n=(450)/(78.4) \\ \approx5\text{ bricks} \end{gathered}`

Hence 5 bricks can be added without breaking the wire.

(b) The string connected to the ceiling will break first as the tension on the wire is the number of bricks times mg.