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A uniform wooden stick of mass 1.6 kg an...

A uniform wooden stick of mass 1.6 kg and length l rests in an inclined mannar on a smooth, vertical wall of height `h(ltl)` such that a small portion of the stick extends beyond the wall. The reaction force of th wall on the stick is perpendicular to the stick. The stick makes an angle of `30^@` with the wall and the bottom of the stick is on a rough floor. The reaction of the wall on the stick is equal in magnitude to the reaction of the floor on the stick. The ratio h/l and the friectional force f at the bottom of the stick are `(g = 10 ms^2)`

A

`h/1 = sqrt(3)/16, f = (16sqrt(3))/3` N

B

`h/1 = 3/16, f = (16sqrt(3))/3 N`

C

`h/1 = (3sqrt(3))/16, f = (8sqrt(3))/3` N

D

`h/1 =(3sqrt(3))/16, f = (16sqrt(3))/3` N

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we will analyze the forces and torques acting on the wooden stick. Here’s a step-by-step breakdown of the solution: ### Step 1: Identify the Forces Acting on the Stick - The weight of the stick (W = mg = 1.6 kg * 10 m/s² = 16 N) acts downward at the center of the stick. - The normal force from the wall (N₁) acts perpendicular to the stick. - The normal force from the floor (N₂) acts upward at the bottom of the stick. - The frictional force (f) acts horizontally at the bottom of the stick. ### Step 2: Set Up the Geometry - The stick makes an angle of \(30^\circ\) with the wall. - The height of the wall is \(h\), and the length of the stick is \(l\). - The height of the stick above the floor can be expressed in terms of \(h\) and \(l\). ### Step 3: Torque Balance - Choose the point where the stick touches the floor as the pivot point (O). - The torque due to the weight of the stick (W) is given by: \[ \text{Torque due to W} = W \cdot \left(\frac{l}{2} \cdot \cos(30^\circ)\right) = 16 \cdot \left(\frac{l}{2} \cdot \frac{\sqrt{3}}{2}\right) = 4l\sqrt{3} \] - The torque due to the normal force from the wall (N₁) is: \[ \text{Torque due to N₁} = N₁ \cdot \left(\frac{2h}{\sqrt{3}}\right) \] - Setting the net torque to zero: \[ N₁ \cdot \left(\frac{2h}{\sqrt{3}}\right) = 4l\sqrt{3} \] ### Step 4: Force Balance in Vertical Direction - The sum of vertical forces must equal zero: \[ N₂ - W = 0 \implies N₂ = W = 16 \text{ N} \] ### Step 5: Force Balance in Horizontal Direction - The sum of horizontal forces must equal zero: \[ f - N₁ \cdot \sin(30^\circ) = 0 \implies f = N₁ \cdot \frac{1}{2} \] ### Step 6: Relate Normal Forces - Since the normal force from the wall is equal to the normal force from the floor (N₁ = N₂): \[ N₁ = 16 \text{ N} \] ### Step 7: Calculate Frictional Force - Substitute \(N₁\) into the equation for friction: \[ f = 16 \cdot \frac{1}{2} = 8 \text{ N} \] ### Step 8: Calculate Height to Length Ratio - From the torque balance equation: \[ 16 \cdot \frac{2h}{\sqrt{3}} = 4l\sqrt{3} \implies 32h = 4l \cdot 3 \implies h = \frac{3l}{8} \] - Therefore, the ratio \( \frac{h}{l} \): \[ \frac{h}{l} = \frac{3}{8} \] ### Final Answers - The ratio \( \frac{h}{l} = \frac{3}{8} \) - The frictional force \( f = 8 \text{ N} \)

To solve the problem, we will analyze the forces and torques acting on the wooden stick. Here’s a step-by-step breakdown of the solution: ### Step 1: Identify the Forces Acting on the Stick - The weight of the stick (W = mg = 1.6 kg * 10 m/s² = 16 N) acts downward at the center of the stick. - The normal force from the wall (N₁) acts perpendicular to the stick. - The normal force from the floor (N₂) acts upward at the bottom of the stick. - The frictional force (f) acts horizontally at the bottom of the stick. ...
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Knowledge Check

  • A circle has radius 12 cm. What is the length of the longest stick that can be placed inside this circle such that the two ends of the stick lie on the circle?

    A
    `22 cm`
    B
    `24 cm`
    C
    `20 cm`
    D
    `26 cm`
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