the turning effect of a force around a fixed point (pivot)
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How do we calculate the moment of a force?
moment = force x perpendicular distance from the line of action of the force to the pivot
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What are these measured in ?
force in newtons and perpendicular distance in metres and moment in newton metres
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How can we increase the moment of a force?
increase the force or the perpendicular distance
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What is refer to as the effort?
the force the person applies
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What is the centre of mass of an object?
the centre of mass of an object is the point where it may be thought be most concentrated
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What can we say about the centre of mass of an object that is suspended from a fixed point
When a suspended objects is in equilibrium its centre of mass is directly beneath the objects
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What can we say about the centre of mass of a symmetrical object
along the axis of symmetry, if there is more than one, the centre of mass is where the axises meet
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What can we say about the moments of the forces acting on an object that isn't turning?
If an object in equilibrium the sum of the anticlockwise moments about any point = the sum of the clockwise moments about that point
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What does equilibrium mean?
the forces are balanced
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How can we use our knowledge of forces and moments to explain why objects at rest don't turn?
if an objects at rest doesn't turn, the opposing forces must be in equqilibrium
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How can we calculate the size of a force (or its perpendicular distance from a pivot) acting on an object that is balanced?
by using and banking using the w1, d1, w2, d2
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What factors affect the stability of an object?
its base width and (wider the better) and centre of mass height (lower the better)
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Why will something topple over?
if the centre of mass isn't within their base
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What can we say about the moments on something when it toppes over?
an objects topples over if the resultant moment about its point of turning is not zero
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How can an objects moving on a circular path at constant speed be accelerating ?
the object accelerates continuously towards the centre of the circle. The acceleration changes the direction of motion of the object, not its speed because the acceleration always acts towards the centre of the circle aka the centripetal action
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What factors affect the centripetal force of an object in circular motion?
speed; if its too fast the swinging thing will fall off, length, if its too close the force won't work because too much force will be needed
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What affects the time period of a pendulum?
only on its length
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How do we measure the time period of a pendulum accurately ?
measure the time of 20 oscillations (swing motion) and divide it by 20 to get one
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how does the motion of a playground swing compare with the motion of a pendulum?
friction at the top of a swing and air resistance will stop it oscillating fits not pushed repeatedly
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Other cards in this set
Card 2
Front
How do we calculate the moment of a force?
Back
moment = force x perpendicular distance from the line of action of the force to the pivot
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