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A man slides down on a telegraphic pole ...

A man slides down on a telegraphic pole with an acceleration equal to one-fourth of acceleration due to gravity.The frictional force between man and pole is equal to (in terms of man's weight `W`)

A

`( w)/( 4)`

B

`( w)/( 2)`

C

`( 3w)/( 4)`

D

w

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to analyze the forces acting on the man as he slides down the telegraphic pole. ### Step-by-Step Solution: 1. **Identify the Forces Acting on the Man:** - The weight of the man (W) acts downward, which can be expressed as \( W = mg \) where \( m \) is the mass of the man and \( g \) is the acceleration due to gravity. - There is a frictional force (F_f) acting upward, opposing the motion of the man. - The man is accelerating downwards with an acceleration \( a = \frac{g}{4} \). 2. **Apply Newton's Second Law:** - According to Newton's second law, the net force acting on the man is equal to the mass of the man multiplied by his acceleration: \[ F_{\text{net}} = ma \] 3. **Set Up the Equation:** - The net force acting on the man can be expressed as: \[ F_{\text{net}} = W - F_f \] - Substituting for \( F_{\text{net}} \): \[ W - F_f = ma \] - Since \( a = \frac{g}{4} \), we can express \( ma \) as: \[ ma = m \cdot \frac{g}{4} \] 4. **Substituting Weight:** - We know \( W = mg \), so we can rewrite the equation: \[ W - F_f = \frac{W}{4} \] 5. **Rearranging the Equation:** - Rearranging gives: \[ F_f = W - \frac{W}{4} \] - This simplifies to: \[ F_f = \frac{4W}{4} - \frac{W}{4} = \frac{3W}{4} \] 6. **Conclusion:** - Therefore, the frictional force \( F_f \) between the man and the pole is: \[ F_f = \frac{3W}{4} \] ### Final Answer: The frictional force between the man and the pole is \( \frac{3W}{4} \).
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