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Question

A rope of length 10 m and linear density 0.5 kg/m is lying length wise on a smooth horizontal floor. It is pulled by a force of 25 N. The tension in the rope at a point 6 m away from the point of application is:

The correct answer is
10 N

Rope Tension Physics Problem Explained

This problem involves calculating the tension in a rope being pulled horizontally across a smooth floor. We need to find the tension at a specific point, 6 m from where the force is applied.

Calculating Acceleration

First, find the total mass of the rope and then its acceleration.

  • Rope Length ($L$) = 10 m
  • Linear Density ($μ$) = 0.5 kg/m
  • Applied Force ($F$) = 25 N
  • Total Mass ($M$) = $L \times μ = 10 \text{ m} \times 0.5 \text{ kg/m} = 5 \text{ kg}$
  • Using Newton's second law, $F = Ma$, the acceleration ($a$) is: $a = \frac{F}{M} = \frac{25 \text{ N}}{5 \text{ kg}} = 5 \text{ m/s}^2$

Determining Tension

The tension at a point in the rope is the force required to accelerate the segment of the rope beyond that point (the part being pulled). We need the tension 6 m from the point of application.

  • The length of the rope segment being accelerated at the 6 m mark is the remaining length: $10 \text{ m} - 6 \text{ m} = 4 \text{ m}$.
  • Calculate the mass ($m$) of this 4 m segment: $m = \text{Length} \times μ = 4 \text{ m} \times 0.5 \text{ kg/m} = 2 \text{ kg}$
  • The tension ($T$) at the 6 m point is the force needed to accelerate this 2 kg mass: $T = m \times a = 2 \text{ kg} \times 5 \text{ m/s}^2 = 10 \text{ N}$

Therefore, the tension in the rope at a point 6 m away from the point of application is 10 N.

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Important Questions from Newton's Laws of Motion

  1. Weight and mass of an object are defined with Newton’s laws of motion. Which among the following is true ?

  2. Which one of the following is not a contact force?

  3. A ball is thrown vertically upward from the ground with a speed of 25.2 m/s. The ball will reach the highest point of its journey in

  4. Which one of the following statements is correct?

  5. When a force of 1 newton act on a mass of 1 kg which is able to move freely, the object moves in the direction of fore with a/an

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