Forces In Balance Flashcards
(27 cards)
What is a scalar quantity?
only has a size (magnitude)
What is a vector quantity?
has both a size and direction
What is a force?
a push or pull that acts on an object due to the interaction with another object
Is force a vector or scalar quantity?
vector quantity
What is a contact force?
when objects are physically touching (e.g., friction, air-resistance, tension, normal contact force)
What is a non-contact force?
when objects are physically separated (e.g., gravitational, electrostatic, magnetic)
What is the same about the interaction pair of forces when two objects interact with each other?
the forces are the same size
What is different about the interaction pair of forces when two objects interact with each other?
forces are in opposite directions
What is the resultant force on an object?
zero
What is the centre of mass?
the point through which the weight of an object can be considered to act
What is the turning effect of a force called?
a moment
What can you say about clockwise and anticlockwise moments on a balanced object?
sum of all the clockwise moments about any point = sum of all the anticlockwise moments about that point
How does a lever reduce the amount of force needed to create a particular sized moment?
by increasing the distance from the pivot
What happens to the moment of a force when a small gear drives a large gear?
moment is increased
What does Newton’s First Law say?
the velocity of an object will only change if a resultant force is acting on it
What is the resultant force on a stationary object?
zero
What is the resultant force on an object moving at a steady speed in a straight line?
zero
What does Newton’s Third Law say?
when two objects interact they exert equal and opposite forces on each other
Resultant force definition
A single force that can replace all the other forces on an object and have the same effect
A-if two forces act in the same direction the resultant is the …
B-if two forces act in opposite direction the resultant force is the …
A-the sum
B-the difference
What is it called when the resultant force on an object is zero?
The forces are balanced
Free body diagrams:
A-arrow length represents the…
B-arrow direction represents the…
A-magnitude of the force
B-Direction of the force
What are scale drawings used for?
They find the resultant of two forces which are not acting along the same line
Where is the centre of mass for a flat symmetrical object
Were the axis of symmetry meet?
