Forces Flashcards
How do you calculate the size of the moment?
M=force x perpendicular distance
How do you get a larger moment?
- larger force
- greater distance
- max moment = force applied at right angle
What is the centre of mass?
The point where the whole mass of an object is concentrated
How do you find the COM of a regular shape?
Find where the lines of symmetry cross
How do you find the COM of an irregular shape?
- Suspend shape & plumbline
- Wait till they stop moving
- Draw line along plumbline
- Repeat from different pivot point
- COM is where lines cross
What is the principle of moments of an object is balanced?
Total anti-clockwise moment = total clockwise moment
How do levers use the idea of balanced moments to make it easier for us to do work?
- increases distance from pivot (less force needed for the same moment)
- force multiplier
What is a resultant moment?
When the anti-clockwise and clockwise moments aren’t equal
How do you make an object more stable?
- low centre of mass
* wide base
How do you calculate the time period of a pendulum?
T=1/frequency
How do you get a greater time period?
Increase the length of the pendulum
How is pressure transmitted in a liquid?
Equally in all directions
How do you calculate pressure?
P= force/cross-sectional area
What is pressure measured in?
Pascals (Pa)
How do hydraulic systems work?
- Small force on small cross-sectional area
- Pressure transmitted equally
- Same pressure on large cross-sectional area
- Larger force
