Answer
The magnitude of the net torque exerted on the branch is $1141.8N.m$
Work Step by Step
The force exerted by each child on the branch is gravitational force $mg$.
As shown in the figure below,
- For the first child $m_1=44kg$, the lever arm $l_1=(1.3m)\sin63$, so the torque exerted on the branch is $$\tau_1=(m_1g)l_1=500N.m$$
- For the second child $m_2=35kg$, the lever arm $l_2=(2.1m)\sin63$, so the torque exerted on the branch is $$\tau_2=(m_2g)l_2=641.8N.m$$
The net torque exerted on the branch is $$\sum\tau=\tau_1+\tau_2=1141.8N.m$$
