turning effect of forces

Question 1

moment of a force

Answer 1

is the product of the force and the perpendicular distance from the pivot to the line of action of the force
moment= F x d

Question 2

principle of moments

Answer 2

when a body is in equilibrium, the sum of clockwise moments about the pivot is equal to the sum of anticlockwise moments about the same pivot

Question 3

centre of gravity

Answer 3

the point through which its whole weight appears to act

Question 4

stability

Answer 4

a measure of its ability to return to its original position after it is slightly displaced

Question 5

Stable equilibrium

Answer 5

When it is slightly tilted, COG rises before returning to its original height
Line of action through its weight is still within its base
Moments of its weight abt the contact point causes the object to return to its original position

Question 6

Unstable equilibrium

Answer 6

COG drop
Line of action through its weight lies outside the base
Moments of weight about the contact point causes it to topple

Question 7

Neutral equilibrium

Answer 7

COG remains at the same height
Line of action through its weight and contact force coincide
Moment of its weight about the contact point is zero, it stays in the position to which it is displaced