Physics GCSE Force (test 1) Flashcards
What type of quantity is force?
- Force is a vector quantity
What do vector quality’s have?
- magnitude
- direction
What are vectors physical quantities?
- force, velocity, displacement
What are scalers?
- only have magnitude but no direction
What are scalers physical quantities?
- speed, distance, mass, temperature
How are vectors represented?
- by an arrow
- the length of the arrow shows its magnitude and the direction of the arrow shows the direction of the quantity?
What is velocity?
- velocity is a vector
What is speed?
- speed is a scaler (length of each arrow is the same)
What is force?
- push or pull on an object that is caused by interacting with something
What is a contact force?
- When the two objects are touching for the force to act
What is a non- contact force?
- Objects do not need to be touching for the force to act
What is an interactional pair?
- pair of forces that are equal and opposite and act on two interacting objects (Newtons Third law)
What are the sun and earth attracted to each other by?
gravitational force (non contact force)
it is an equal but opposite attraction
When is an object in equilibrium?
- When all of the forces on an object combine to give a resultant force of zero
What does three forces on a scale diagram form?
- a triangle
What is the turning effect of a force?
- a moment
What is the equation for the moment of a force?
moment of a force= Force X Distance
What is the distance in a moment?
- Perpendicular distance from the pivot to the line of action of force
What does the force of a spanner cause?
- a turning effect of a moment on the nut (which acts as a pivot)
How does the force or distance affect the moment?
- the larger force or longer distance would mean a larger moment.
How do you get the maximum moment?
- push at right angles (perpendicular) to the spanner
How does pushing at other angles affect the distance and moment?
- smaller distance - so a smaller moment
When is an object balanced?
- if the total anticlockwise moment equals the total clockwise moment about a pivot
What does levers increase?
- the distance from the pivot at which the force is applied
Why do levers make it easier to do work?
M=F X D
- less force is needed to get the same moment
What are Gears?
- Circular disks with teeth around the edge
What do the gears teeth do?
- interlock so the turning one causes another one to turn in the opposite direction
What are gears used for?
- to transmit the rotational effect of a force from one place to another
What will a force transmitted to a larger gear cause?
- a bigger moment as the distance to the pivot is bigger
Which turns slower the larger gear or the smaller gear?
larger gear turns slower
What is weight?
- force acting on an object due to gravity (measured in newtons)
Where can the force act from?
- single point on the object (called its centre of mass)
What is the centre of mass?
- the point where you can assume the whole mass is concentrated
What is Newtons Third Law of motion?
When two objects interact with each other, they exert equal and opposite forces on each other
What is resultant force?
- single force that has the same effect as all the forces acting on the object
How can you find the centre of mass of a 2D object?
- put a whole in one corner of the card and suspend the card from a rod
- use a plumb line to draw a vertical line on the card from the rod
- repeat procedure, hanging the card from a different corner
-the point where the two lines meet is the centre of mass
