5) Turning Effect of Forces Flashcards
What is the turning effect of a force also known as?
moment or torque
What is the formula for the moment of a force ?
moment = Force X Perpendicular Distance
In what direction can a force turn about a pivot ?
Clockwise and anti-clockwise
Define the principle of moments
When an object is in equilibrium, the sum of clockwise moments about a pivot is equal to the sum of anti-clockwise moment about the same pivot.
Define center of gravity.
It is a point in an object where the whole weight of the object seems to act.
What makes an object more stable? (2 factors)
1) Lowering the center of gravity of the object
2) Increasing the base area of the object
What is the unit for moment?
newton-meter (Nm)
Formula line using principle of moment
(There are 2 lines)
Taking moments about the pivot
Total clockwise moments = total anti-clockwise moments
Identify the moments created by the 4 forces (A, B, C and D).
Anti -clockwise moments: Force A and D
clockwise moments: Force C
No moments: Force B
What is the perpendicular distance of force F to the pivot?
100 cm
(Remember that perpendicular distance must be measured from the pivot to the line of action of the force)
What is unstable equilibrium?
A body continues to move away from the original position after being displaced slightly.
What is stable equilibrium?
A body returns to its original position after being displaced slightly.
State two ways to make an object more stable.
- Lowering the center of gravity
- Increasing the base area
Explain why the car will topple.
The center of gravity of the car passes beyond the edge of the base area, creating an anti-clockwise moment about the tip of the wheel causing it to topple.
Explain why the racing car is more stable than the van.
Racing car has a lower center of gravity than the van.
The base area of the racing car is larger than the base area of the van.
Position 1.
(As it is more massive on the left than on the right.)
