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Grade upto college level Electric Current

a long rubber tube having mass 0.9 kg is fastened to a fixed support and the free end of the tube is attached to a chord which passes over a pulley and supports an object with a mass of 5kg .if the tube is struck by a transverse blow at one end,the time required for the pulse to reach the other end is[linear density of wire is 49/625kg/m

Profile image of Amit Saxena
12 Years agoGrade upto college level
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1 Answer

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ApprovedApproved Tutor Answer1 Year ago

To determine the time required for a pulse to travel through the rubber tube, we need to consider the properties of the tube and the wave speed in it. The speed of a wave in a medium is influenced by the medium's tension and linear density. In this case, we can calculate the wave speed using the formula:

Wave Speed in a Medium

The speed of a wave (v) in a stretched string or tube can be expressed as:

v = √(T/μ)

Where:

  • T = tension in the string (in Newtons)
  • μ = linear density of the medium (in kg/m)

Calculating Tension

In this scenario, the tension in the rubber tube is due to the weight of the mass hanging from the chord. The mass (m) is given as 5 kg. The tension can be calculated using the formula:

T = m * g

Where:

  • g = acceleration due to gravity (approximately 9.81 m/s²)

Substituting the values:

T = 5 kg * 9.81 m/s² = 49.05 N

Linear Density

The linear density (μ) of the rubber tube is given as 49/625 kg/m. We can convert this to a decimal for easier calculations:

μ = 49/625 = 0.0784 kg/m

Calculating Wave Speed

Now that we have both the tension and the linear density, we can calculate the wave speed:

v = √(T/μ) = √(49.05 N / 0.0784 kg/m)

Calculating this gives:

v = √(625.64) ≈ 25.01 m/s

Time for Pulse to Travel the Length of the Tube

Next, we need to find the time (t) it takes for the pulse to travel the length of the tube. The time can be calculated using the formula:

t = L/v

Where:

  • L = length of the tube (in meters)
  • v = wave speed (in m/s)

Since the length of the tube is not provided in the question, we can express the time in terms of L:

t = L / 25.01

Final Thoughts

In summary, the time required for the pulse to reach the other end of the rubber tube depends on its length. If you know the length of the tube, you can substitute that value into the equation to find the exact time. For example, if the tube is 10 meters long, the time would be:

t = 10 m / 25.01 m/s ≈ 0.4 seconds

Thus, the time for the pulse to travel through the tube is directly related to its length and the calculated wave speed.