Question

An ethernet cable is 3.80 m long and has a mass of 0.210 kg. A transverse pulse is produced by plucking one end of the taut cable. The pulse makes four trips down and back along the cable in 0.735 s. What is the tension in the cable?

Answer 1

Answer:

$T=94.54N$

Explanation:

The tension in a cable is given by:

$T=\mu v^2(1)$

Where $\mu$ is the mass density of the cable and v is the speed of the cable's pulse. These values are defined as:

$\mu=\frac{m}{L}(2)\\v=\frac{d}{t}$

The pulse makes four trips down and back along the cable, so $d=4(2L)$

$v=\frac{8L}{t}(3)$

Replacing (2) and (3) in (1), we calculate the tension in the cable:

$T=\frac{m}{L}(\frac{8L}{t})^2\\T=\frac{64mL}{t^2}\\T=\frac{64(0.21kg(3.80m))}{(0.735s)^2}\\T=94.54N$