# 0.3 Transverse pulses  (Page 5/6)

 Page 5 / 6

## Travelling pulse

1. A pulse is passed through a rope and the following pictures were obtained for each time interval:
1. Complete the following table for a particle in the medium:
 time (s) 0,00 0,25 0,50 0,75 1,00 1,25 1,50 1,75 2,00 position (mm) velocity (mm.s ${}^{-1}$ )
2. Draw a position vs. time graph for the motion of the particle at $3\phantom{\rule{2pt}{0ex}}\mathrm{cm}$ .
3. Draw a velocity vs. time graph for the motion of the particle at $3\phantom{\rule{2pt}{0ex}}\mathrm{cm}$ .
4. Draw a position vs. time graph for the motion of the pulse through the rope.
5. Draw a velocity vs. time graph for the motion of the pulse through the rope.

## Transmission and reflection of a pulse at a boundary

What happens when a pulse travelling in one medium finds that medium is joined to another?

## Investigation : two ropes

Find two different ropes and tie both ropes together. Hold the joined ropes horizontally and create a pulse by flicking the rope up and down. What happens to the pulse when it encounters the join?

When a pulse is transmitted from one medium to another, like from a thin rope to a thicker one, the nature of the pulse will change where it meets the boundary of the two media (i.e. where the two ropes are joined). Part of the pulse will be reflected and part of it will be transmitted. [link] shows the general case of a pulse meeting a boundary. The incident pulse is the one that arrives at the boundary. The reflected pulse is the one that moves back, away from the boundary. The transmitted pulse is the one that moves into the new medium, away from the boundary. The speed of the pulse depends on the mass of the rope; the pulse is faster in the thinner rope and slower in the thick rope. When the speed of the pulse increases, the pulse length will increase. If the speed decreases, the pulse length will decrease.

Consider a pulse moving from a thin rope to a thick rope. As the pulse crosses the boundary, the speed of the pulse will decrease as it moves into the thicker rope. The pulse will move slower, so the pulse length will decrease. The pulse will be reflected and inverted in the thin rope. The reflected pulse will have the same length and speed but will have a smaller amplitude. This is illustrated in [link] .

When a pulse moves from a thick rope to a thin rope, the opposite will happen. As the pulse crosses the boundary, the speed of the pulse will increase as it moves into the thinner rope. The pulse in the thin rope will move faster, so the pulse length will increase. The pulse will be reflected but not inverted in the thick rope. The reflected pulse will have the same length and speed but will have a smaller amplitude. This is illustrated in [link]

## Pulses at a boundary i

1. Fill in the blanks or select the correct answer: A pulse in a heavy rope is traveling towards the boundary with a thin piece of string.
1. The reflected pulse in the heavy rope will/will not be inverted because .
2. The speed of the transmitted pulse will be greater than/less than/the same as the speed of the incident pulse.
3. The speed of the reflected pulse will be greater than/less than/the same as the speed of the incident pulse.
4. The pulse length of the transmitted pulse will be greater than/less than/the same as the pulse length of the incident pulse.
5. The frequency of the transmitted pulse will be greater than/less than/the same as the frequency of the incident pulse.
2. A pulse in a light string is traveling towards the boundary with a heavy rope.
1. The reflected pulse in the light rope will/will not be inverted because .
2. The speed of the transmitted pulse will be greater than/less than/the same as the speed of the incident pulse.
3. The speed of the reflected pulse will be greater than/less than/the same as the speed of the incident pulse.
4. The pulse length of the transmitted pulse will be greater than/less than/the same as the pulse length of the incident pulse.

Introduction about quantum dots in nanotechnology
what does nano mean?
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
it is a goid question and i want to know the answer as well
Maciej
Abigail
for teaching engĺish at school how nano technology help us
Anassong
Do somebody tell me a best nano engineering book for beginners?
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
what is fullerene does it is used to make bukky balls
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
so some one know about replacing silicon atom with phosphorous in semiconductors device?
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
for screen printed electrodes ?
SUYASH
What is lattice structure?
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
what's the easiest and fastest way to the synthesize AgNP?
China
Cied
types of nano material
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
what is nano technology
what is system testing?
how did you get the value of 2000N.What calculations are needed to arrive at it
Privacy Information Security Software Version 1.1a
Good
Got questions? Join the online conversation and get instant answers!