6. the diagram below shows the top view of a door that is 2.0 m wide. two forces are applied to the door as…

6. the diagram below shows the top view of a door that is 2.0 m wide. two forces are applied to the door as indicated in the diagram. what is the net torque on the door with respect to the hinge?

6. the diagram below shows the top view of a door that is 2.0 m wide. two forces are applied to the door as indicated in the diagram. what is the net torque on the door with respect to the hinge?

Answer

Explanation:

Step1: Recall torque formula

The formula for torque is $\tau = rF\sin\theta$, where $r$ is the distance from the pivot - point (hinge), $F$ is the force, and $\theta$ is the angle between the position - vector from the pivot to the point of application of the force and the force vector.

Step2: Calculate torque due to first force

For the first force $F_1 = 10\ N$ with $r_1=1.0\ m$ and $\theta_1 = 60^{\circ}$, $\tau_1=r_1F_1\sin\theta_1=(1.0\ m)\times(10\ N)\times\sin60^{\circ}=(1.0\ m)\times(10\ N)\times\frac{\sqrt{3}}{2}=5\sqrt{3}\ N\cdot m$ (counter - clockwise, positive).

Step3: Calculate torque due to second force

For the second force $F_2 = 10\ N$ with $r_2 = 2.0\ m$ and $\theta_2=60^{\circ}$, $\tau_2=r_2F_2\sin\theta_2=(2.0\ m)\times(10\ N)\times\sin60^{\circ}=(2.0\ m)\times(10\ N)\times\frac{\sqrt{3}}{2}=10\sqrt{3}\ N\cdot m$ (clockwise, negative).

Step4: Calculate net torque

The net torque $\tau_{net}=\tau_1-\tau_2=5\sqrt{3}\ N\cdot m- 10\sqrt{3}\ N\cdot m=- 5\sqrt{3}\ N\cdot m\approx - 8.66\ N\cdot m$. The negative sign indicates a clockwise net torque.

Answer:

$-5\sqrt{3}\ N\cdot m\approx - 8.66\ N\cdot m$