7.5 - stability

Question 1

Define stability

Answer 1

A measurement of a body’s ability to maintain its stable position

Question 2

what is a degree of stability

Answer 2

a variable that depends on how much its center of gravity changes when its moved

Question 3

Describe a body in stable equilibrium

Answer 3

If the body is displaced and released, it will return back to its equilibrium position

When at rest the object’s center of mass is directly below the point of support

Question 4

Describe an object in unstable equlilibrium

Answer 4

If the body is displaced and released, it will NOT return back to its equilibrium position

the object’s center of mass is directly above the point of support

Question 5

Define tilting

Answer 5

1. an object at rest on a flat surface is acted on by a force that raises it up by 1 side

Question 6

Calculating force needed to tilt an object

Answer 6

clockwise moment about pivot = Fd

(d = perpendicular distance between pivot to line of action of f)

anti-clockwise moment about pivot = w(b/2)

(b = base length, w = objects weight)

Fd > w(b/2)

Question 7

Define toppling

Answer 7

tilted object will topple over if tilted too far

• the weight moves past the pivort

Question 8

When will an object on a slope topple over

Answer 8

when the line of action of its weight lies beyond a support force

Question 9

The object on a slope diagram

• calculate force that’s parallel & the force perpendicular to the slope

Answer 9

Parallel = Wsinø

Perpendicular = Wcosø