do now can you read the hydraulics pages of your books (p157)?
TRANSCRIPT
![Page 1: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/1.jpg)
Do now Can you read the hydraulics pages of your books (p157)?
![Page 2: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/2.jpg)
Today’s lesson
• Know what the turning effect of a force is
• Know that the moment of a force depends on force and the distance from the pivot
• Know the principle of moments
![Page 3: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/3.jpg)
What happens when you try to open a door with one finger?
Where do you push?
Hi, my name is Mr Stick
hinges
![Page 4: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/4.jpg)
Do you push near the hinges?
I can’t do it!
![Page 5: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/5.jpg)
Do you push far from the hinges?
That’s easier!
![Page 6: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/6.jpg)
Moments – Turning forces
![Page 7: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/7.jpg)
The turning effect of a force depends on two things;
The size of the force
Obviously!
![Page 8: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/8.jpg)
The turning effect of a force depends on two things;
The distance from the pivot (axis of rotation)
Not quite so
obvious!
Axis of rotation
![Page 9: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/9.jpg)
Turning effect of a force
The turning effect of a force is called the moment of the force
The moment is calculated by multiplying the force by the distance from the pivot
![Page 10: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/10.jpg)
Turning effect of a force – moment of a force
Moment (Nm) = Force (N) x distance from pivot (m)
Note the unit is Nm, not N/m!
![Page 11: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/11.jpg)
A simple example!
nut
spanner (wrench)
50 N
0.15 m
![Page 12: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/12.jpg)
A simple example!
nut
spanner (wrench)
50 N
0.15 m
Moment = Force x distance from pivot
Moment = 50 N x 0.15 m
Moment = 7.5 Nm
![Page 13: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/13.jpg)
What do you do if the nut won’t move and you can’t push harder?!
nut
spanner (wrench)
50 N
0.15 m
![Page 14: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/14.jpg)
Get a longer spanner!
nut
spanner (wrench)
50 N
0.25 m
Moment = Force x distance from pivot
Moment = 50 N x 0.25 m
Moment = 12.5 Nm
![Page 15: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/15.jpg)
More than one force
Take an uneven see-saw for an example
Do you think we’ll be safe in this power point?
It’s not looking good!
pivot
![Page 16: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/16.jpg)
If the see-saw is balanced, what must be the weight of the dog on the left?
pivot
1.2 m 2.2 m
110 N? N
![Page 17: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/17.jpg)
The force on the left is trying to turn the see-saw anticlockwise about the pivot
pivot
1.2 m 2.2 m
110 N? N
![Page 18: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/18.jpg)
The force on the right is trying to turn the see-saw clockwise about the pivot
pivot
1.2 m 2.2 m
110 N? N
![Page 19: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/19.jpg)
If the see-saw balances, the turning effect anticlockwise must equal the turning effect
clockwise
pivot
1.2 m 2.2 m
110 N? N
Anticlockwise moment clockwise moment=
![Page 20: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/20.jpg)
Anticlockwise moment = clockwise moment? X 1.2 = 110 x 2.2
? X 1.2 = 242? = 242/1.2? = 201.7 N
pivot
1.2 m 2.2 m
110 N? N
Anticlockwise moment clockwise moment=
![Page 21: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/21.jpg)
Rotational Equilibrium
When there is no resultant moment on an object (when anticlockwise moments = clockwise moments) we say the object is in rotational equilibrium.
YouTube - Alan Partridge's Apache office
![Page 22: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/22.jpg)
Whew! We seemed to have
survived the power point
pivot
![Page 23: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/23.jpg)
Don’t speak too
soon!
pivot
BO
MB
![Page 24: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/24.jpg)
pivot
BO
MB
![Page 25: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/25.jpg)
pivot
BO
MB
![Page 26: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/26.jpg)
pivotBO
MB
![Page 27: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/27.jpg)
pivot
![Page 28: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/28.jpg)
pivot
Nice one!
![Page 29: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/29.jpg)
pivot
You’ll have to do some questions
now, or he’ll kill me too!
![Page 30: Do now Can you read the hydraulics pages of your books (p157)?](https://reader035.vdocument.in/reader035/viewer/2022062313/56649d215503460f949f5f31/html5/thumbnails/30.jpg)
pivot
Read pages 162 and 163 and make notes. Then try the questions.