Question

3. A very light bamboo fishing rod 3.0 m long is secured to a boat at the bottom end. It is

Answer 1

The image in the attachment describes the situation of the fishing rod.

Answer: F = 10.8 N

Explanation: The image shows a fishing rod attached to an axis. To stay in equilibrium, Torque must be equal for the force of magnitude 18N and for the unknow force.

Torque (τ) is a measure of a force's tendency to cause rotation and, in physics, defined as:

τ = F.r.sin(θ)

F is the force acting on the object;

r is distance between where the torque is measured to where the force is applied;

θ is the angle between F and r;

For the fishing rod:

$\tau_{1} = \tau_{2}$

$F_{1}.r_{1}.sin(\theta) = F_{2}.r_{2}.sin(\theta)$

Assuming part (1) is related to unknown force:

$F = \frac{F_{2}.r_{2}.sin(\theta}{r_{1}.sin(\theta) }$

Replacing the corresponding values:

$F = \frac{18*1.8*sin(30)}{3*sin(30)}$

$F = \frac{18*1.8}{3}$

F = 10.8

The fishing line exert on the the rod a force of 10.8N.