Turning forces and motion Flashcards
What does it mean for something to turn, with an example?
For an object to turn means for it to rotate about a point or change direction. For example: when you bend your arm, the arm acts as a lever, and the elbow is the pivot.
What is a lever?
A lever is an object that turns when a force is applied to it.
What is a pivot?
A pivot (or fulcrum) is the fixed point around which the lever turns.
What do forces applied to a lever create?
Forces applied to a lever create a turning effect.
What is a moment?
A moment of a force describes its turning effect of a force.
What does the moment of a force depend on?
The moment of a force depends on:
*The size of the force (greater force = greater moment).
*The perpendicular distance between the pivot and the point where the force is applied (greater distance = greater moment).
What is the equation for calculating a moment?
You can find a moment using the equation: moment=force×distance
What does distance in the equation refer to?
Distance refers to the perpendicular distance from the pivot to the point where the force acts.
What is the unit of moment and why?
Since the init of force is the newton and the unit of distance is the metre, the unit of moment is the newton×metre, written as newton metre or N m.
What do you have to remember when writing the unit of a moment?
Always write moment units as Nm, with an uppercase “N” and lowercase “m”.
What does an object need to be balanced, and what readjustments would need to be made if one side is misbalanced?
For an object to be in equilibrium (balanced), the total clockwise moment must be equal to the total anticlockwise moment. If forces or distances change on one side of the pivot, the other side must adjust to maintain balance.
What is an example of balancing?
Example: A seesaw balances when the moments on both sides are equal and opposite. If one person moves further from the pivot, their turning effect increases, and the other person must move closer to balance it.
