# Wave speed equation

## Homework Statement

y(x,t)=0.8/{(4x+5t)^2+5 }represents a moving pulse,where x and y are in metre and tin second.Then choose the options.

(a)Pulse is moving in positive X axis
(b)In 2 secs,it will travel a displacement of 2.5m
(c)It's maximum displacement is 0.16m
(d)It is a symmetric pulse

## The Attempt at a Solution

So since it is a general transverse wave so it's velocity is 1.25 towards negative X axis.

I can't say about the amplitude unless I know the shape of the pulse so How should I graph this and work out the other options

## Answers and Replies

DrClaude
Mentor
There is no t in the equation.

My mistake...sorry

ehild
Homework Helper

## Homework Statement

y(x,t)=0.8/{(4x+5t)^2+5 }represents a moving pulse,where x and y are in metre and tin second.Then choose the options.

(a)Pulse is moving in positive X axis
(b)In 2 secs,it will travel a displacement of 2.5m
(c)It's maximum displacement is 0.16m
(d)It is a symmetric pulse

## The Attempt at a Solution

So since it is a general transverse wave so it's velocity is 1.25 towards negative X axis.

I can't say about the amplitude unless I know the shape of the pulse so How should I graph this and work out the other options
How does it look at t=0?

How does it look at t=0?
At t=0,y is 0.16m

DrClaude
Mentor
At t=0,y is 0.16m
At ##t=0##, ##y## is a function of ##x##.

I got the graph and it looks symmetric to Y axis with y=0.16 m at t=0

DrClaude
Mentor
I got the graph and it looks symmetric to Y axis with y=0.16 m at t=0
You should calculate the position xmax of the maximum of y (it will be a function of t), and then the value of y(xmax,t). That will tell you what the maximum displacement is. You can then check the symmetry of y around xmax.

ehild
Homework Helper
I got the graph and it looks symmetric to Y axis with y=0.16 m at t=0

Yes, it is symmetric to the Y axis at t=0. At what x does the function $$y(x)=\frac{0.8}{(4x)^2+5}$$ have its maximum, and what is the maximum displacement from equilibrium?
At what x is the maximum of y(x,t) at a different time, at t = 2 s, for example?