Yr 10 GCSE forces revision Flashcards
Define non contact forces
A non-contact force occurs because either attraction or repulsion between two objects - with no contact. Always a field contact e.g. Gravitational force
Define contact forces
A forces occurs due to the contact between two different objects - no field link. E.g. frictional force
What is a vector quantity?
This is a quantity described with both magnitude (size) and direction. E.g. weight
What is a scalar quantity?
This is a quantity described only of its magnitude (size). E.g. Weight
Give three examples of scalar quantities
Any three of: mass, distance, speed, energy, time, power, force
Give three examples of vector quantities
Acceleration, force, velocity
What is weight?
The downwards force due to gravity
What is up-thrust?
The upward force exerted upwards on an object in a fluid
What is friction?
A resistive force due to 2 objects in contact
What is air resistance?
resistive force due to moving through the air
What is lift?
A force that uses motion for a an object to move up
Give three examples of contact forces
Any three of: Friction, Air resistance, Tension, Reaction
Give three examples of non-contact forces
Gravitational forces, Electrostatic forces, Magnetism
Do forces occur in pairs
Yes!
If a duck is not moving, floating on water, what pair of forces is acting upon it?
Weight downwards, and up-thrust Upwards
What is the difference between weight and mass?
Mass is the amount of matter in something, weight is the force acting downwards due to gravity
What is weight measured in?
Newtons
What is mass measured in?
Kilograms
What is the meaning of gravitational field strength?
How much force gravity exerts per unit mass
What is the unit for gravitational field strength
N/Kg
What increases the Gravitational field strength?
The larger the object and the closer they are
Why are you weightless in space?
There is no forces pushing down on you giving you weight
What is the equation that includes weight?
weight = mass x Gravitational Field strength
What is the definition of the centre of mass?
The point in an object where the weight appears to act