3b.1 - Turning Forces and Centre of Mass Flashcards
What does force on a spanner cause?
A turning force or moment or moment on the nut
What can cause a larger moment? (2)
- Increased force
- Distance from the handle to the pivot
How how do you calculate moments?
Force x perpendicular distance from the line of action of the force to the pivot
How do you get the maximum moment?
Push perpendicular to the hammer
Why does pushing the spanner at another angle to 90 make the moment smaller?
Decreases distance
What is the centre of mass?
The point where the whole mass is concentrated
How do you calculate the centre of mass? (5)
- Set up clamp, stand and boss and put a cork inside the clamp and attach a plumbline to it
- Suspend the drawn shape near the edge loosely
- Draw a line where the plumbline falls on the shape
- Repeat 3 more times with the suspension point at different points around the outside
- The centre of mass is where the lines cross
When will an object not turn?
When clockwise and anticlockwise moments are equal
What do levers do?
Increase the distance from the pivot at which the force is applied
How are levers force multipliers?
They reduce the amount of force that’s needed to get the same moment by increasing the distance
When will an object turn?
If the total anticlockwise moment does not equal the clockwise motion
What objects are the most stable? (2)
- Low centre of mass
- Wide base
When will an object start to tip?
If it’s centre of mass moves beyond the edge of it’s base
