Question

A wave in slinky travelled to and fro in \[5{\text{ }}sec\] the length of the slinky is \[5{\text{ }}m.\] The velocity of wave is

A) \[10{\text{ }}m{s^{ - 1}}\]
B) \[5m{s^{ - 1}}\]
C) \[2m{s^{ - 1}}\]
D) $25m{s^{ - 1}}$

Answer 1

Hint: To solve this question, i.e., to find the velocity of the wave. We will consider the total distance as the wave is moving to and fro, then in the formula of velocity, we will apply the values given to us in the question, then with that we will get our required answer.

Complete step by step answer:
We have been given a figure where a wave in slinky travelled to and fro in \[5{\text{ }}sec\] and the length of the slinky is \[5{\text{ }}m.\] We need to find the velocity of wave.
Since, it is given that the wave moves to and fro in the slinky. Therefore, the total distance, \[\Rightarrow d{\text{ }} = {\text{ }}2 \times 5{\text{ }} = {\text{ }}10{\text{ }}m\]
The given time, \[t{\text{ }} = {\text{ }}5{\text{ }}\sec \]
We know that, Velocity $ = \dfrac{{total{\text{ }}distance}}{{time}}$
On putting the values in the above formula, we get
Velocity \[ = \dfrac{{10}}{5}\]
Velocity \[ = 2{\text{ }}m{s^{ - 1}}\]
So, the velocity of wave is \[2{\text{ }}m{s^{ - 1}}.\]

Thus, option (C) is correct.

Note: Students must be wondering, what does slinky stand here. So, the slinky is a simple toy, it consists of a helical spring made up of plastic or metal. Slinky shows the effects of many phenomena at once. For example, if a slinky is not moving, it will possess potential or stored energy. But if it starts down the stairs, gravity pulls on it, then the potential energy is converted to kinetic energy. Slinky shows characteristics like inertia, as If a slinky is standing on its end without any external force, it will stay like it, just like inertia.