# Experiments / Vector triangles

Watch
Announcements
#1
For the exam we need to know how to explain how experiments carried out by Galileo overturned Aristotle's ideas of motion, describe an experiment to determine g the acceleration of free fall, describe an experiment to determine the centre of gravity of an object, describe how GPS and air-bags work, describe an experiment to determine the young modulus of a material
What do you reckon is the best way to be able to carry out these parts of the specification?
The book is not the best so should I learn it from the mark scheme?- but then I bet the same thing obviously wouldn't recur... :/
Or can someone on here post a long answer to these?- please
0
6 years ago
#2
(Original post by MathMeister)
For the exam we need to know how to explain how experiments carried out by Galileo overturned Aristotle's ideas of motion, describe an experiment to determine g the acceleration of free fall, describe an experiment to determine the centre of gravity of an object, describe how GPS and air-bags work, describe an experiment to determine the young modulus of a material
What do you reckon is the best way to be able to carry out these parts of the specification?
The book is not the best so should I learn it from the mark scheme?- but then I bet the same thing obviously wouldn't recur... :/
Or can someone on here post a long answer to these?- please
Well you could've just google Galileo... he's famous for 3 things

1. overturning Aristotles ideas about falling objects with a freefall demo (off the leaning tower of pisa)
2. a theory of pendulums that came from timing swinging chandeliers (with his pulse)
3. improvements to the refracting telescope

see here http://www.math.wichita.edu/history/men/galileo.html

1 & 2 both lead to methods that can be used to determine g

http://www.nuffieldfoundation.org/pr...on-due-gravity

or
http://en.wikipedia.org/wiki/Kater%2...with_pendulums
0
6 years ago
#3
(Original post by MathMeister)
For the exam we need to know how to explain how experiments carried out by Galileo overturned Aristotle's ideas of motion, describe an experiment to determine g the acceleration of free fall, describe an experiment to determine the centre of gravity of an object, describe how GPS and air-bags work, describe an experiment to determine the young modulus of a material
What do you reckon is the best way to be able to carry out these parts of the specification?
The book is not the best so should I learn it from the mark scheme?- but then I bet the same thing obviously wouldn't recur... :/
Or can someone on here post a long answer to these?- please

Experiment to measure the acceleration due to gravity:

-Two circuits are interconnected by one switch (meaning when the switch is pushed upwards, Circuit one becomes complete while a gap is created in the second one and vice versa)
-In circuit 1, an electromagnet is connected to a power supply
-In circuit 2, a stop clock is connect to a trap-door switch

The formula used will s=at+1/2at^2
But since u=0, s=h and a=g
the new formula will be: h=1/2gt^2

Carrying out experiment:
1. Push the switch so circuit one is completed and the electromagnet turns on
2. Connect the Iron with the electromagnet (Since its iron, it will be attracted to the electromagnet)
3. Pull the switch downwards, so electromagnet switches off and the ball falls down. Simultaneously, circuit will be completed and the timer will start.
4. The ball with fall and hit the trap-door switch, creating a gap in Circuit 2 and the timer will immediately stop.
5. The time on the timer will be recorded.
6. The height between the electromagnet and the trapdoor switch is measured using a meter rule or a measuring tape.
7. Repeat the experiment at different heights and record the time taken.
8. Draw a graph of h (height) against t^2 (square of time) as the formula is h=t^2 (from h=1/2gt^2)
9. The gradient of the graph will 1/2g
10. Hence, the gradient of the graph multiplied by 2 will give us the value of g.

The picture of the experiment can found at:
http://astarmathsandphysics.com/a-le...l-m5b0f1e0.gif
0
6 years ago
#4
Experiment to calculate the young's modulus:
In this experiment, we are going to calculate the young's modulus

Apparatus:
-Micrometer to measure the diameter of the wire (which will used to calculate the cross-sectional area of the wire)
-A measuring tape/meter scale to measure the length of the wire.
-Thin Copper wire of length at least 2m (The wire is thin and long because long and thin materials give more extension so the value of young's modulus will more precise and accurate)

Carrying out the experiment:
-The diameter of the copper wire is measured using the micro-meter at different points on the wire and the average value is calculated.
-One end of a copper wire is clamped between the 2 wooden blocks while the other end connected to weight hanger over a smooth pulley.
-A strip of sticky tape is attached to the wire so that its edge s on the lower end of the meter scale.
-Weights are placed on the hanger in 200g (2N) increments and extension is loaded after each increment.
-The value of stress at each increment is calculated by: weight of mass on the hanger/cross-sectional area of the wire.
-The value of strain at each increment is calculate by: extension of the wire in m/original length of wire in m
-A graph of stress against strain is plotted
-The gradient of the graph will give the value of the Young's Modulus!

Precautions:
To prevent the wire from damaging the eye if it snatches, Safety goggles must be worn.
- Safety shoes must be worn to prevent feet from getting hurt in case the wire snatches and the hangers falls, along with the masses!
0
X

new posts
Back
to top
Latest
My Feed

### Oops, nobody has postedin the last few hours.

Why not re-start the conversation?

see more

### See more of what you like onThe Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

### Poll

Join the discussion

#### Poll: What factors affect your mental health most right now? Post-lockdown edition

6.07%
Uncertainty around my education (101)
11.35%
Uncertainty around my future career prospects (94)
10.56%
Lack of purpose or motivation (110)
12.36%
Lack of support system (eg. teachers, counsellors, delays in care) (44)
4.94%
Impact lockdown had on physical health (48)
5.39%
Social worries (incl. loneliness/making friends) (99)
11.12%
Financial worries (60)
6.74%
Concern about myself or my loves ones getting/having been ill (40)
4.49%
Exposure to negative news/social media (56)
6.29%
Difficulty accessing real life entertainment (26)
2.92%
Lack of confidence in making big life decisions (86)
9.66%
Worry about missed opportunities during the pandemic (72)
8.09%