Chapter P8- Forces in Balance Flashcards
What is displacement?
What is distance?
What is a vectors?
What are scalars?
What is magnitude?
What does the direction of the arrow in representing a vector show?
What does the length of the arrow in representing a vector show?
Distance without a change of direction
How far something has to travel to get somewhere (to its destination)
Physical quantities that have direction
Physical quantities that have size, but no specific direction
The size of a quantity
The direction of the vector quantity
The magnitude of the vector quantity.
What three things can forces do to an object?
What are forces measured in?
What are contact forces caused by?
What are two examples of contact forces?
What are non contact forces?
What are two examples of non contact forces?
What does Newton’s Third Law state?
What do free body diagrams show?
How do resultant forces occur?
What can then be calculated and what is this known as?
When do we subtract in resultant forces?
When do we add in resultant forces?
Change the shape of an object, change its motion or its state of rest
Newton’s (N)
Forces which are caused by 2 objects touching each other
eg Friction, air resistance
Forces which have an effect from a distance
Magnitude forces, the force due to gravity
That when two objects interact with each other they exert equal and opposite forces on each other
The forces on an object
When if 2 or more forces act on an object.
The overall force (known as the resultant force)
When in opposite directions
When in the same directions.
What doesn’t change if the forces are balanced?
What two things can happen if something is balanced?
What changes when the forces are unbalanced?
What three things can happen if something’s unbalanced?
What can levers help with?
What would otherwise be required?
Why are levers known as force multipliers?
What are moments and what are they caused by?
What two things are always involved in moments?
What two things does the size of the moment depend on?
To the movement
It will continue moving at the same speed
It will stay still
There’s a change to the movement
It will accelerate
It will decelerate
It will change direction
Moving objects
A larger force
Because they don’t need the full force to move the object
Moments are turning effects caused by a force
A pivot and a lever
The size of the force and the distance between the pivot and the force.
What is the formula to calculate moments?
What is an object called when it is balanced?
How does this happen?
What are moments measured in?
What two things does a low gear give?
What does this mean?
What two things does a high gear give?
What does this mean?
What is the centre of mass of an object?
Moments= Force x Distance perpendicular to the pivot
In equilibrium
When the clockwise moments are equal to the anticlockwise moments.
Newton metres (Nm)
Low speed and a high turning effect
ie More force
High speed and a low turning effect
ie Low force
The point at which its mass can be thought of as being concentrated.
What will the centre of mass be if you suspend an object?
What happens at this point and doesn’t the weight exert?
Where is the centre of mass for symmetrical objects?
How can you find the centre of mass for an asymmetrical object?
Where will the centre of mass be?
What can we use to find the resultant force?
What does this involve using?
What two things must there be for an object to be in equilibrium?
It will come to rest with its centre of mass directly below the point of suspension
The object is in equilibrium and the weight doesn’t exert a turning force on the object
Where the lines of symmetry meet
By suspending the object and drawing a line vertically downwards
Where 2 or more of these lines overlap
We use parallelogram of forces
Accurate scaled diagrams
- A resultant force of zero on the object
- No overall turning effect on the object.
