Forces- Physics Paper 2 Flashcards
What does a vector quantity have?
A magnitude and a direction
What does a scalar quantity have?
Just a magnitude
What are examples of vector quantities?
force, velocity, displacement, acceleration, momentum
What are examples of scalar quantities?
speed, distance, mass, temperature ,time
What is a force?
A push or a pull that acts on an object
What is the unit of force?
Newtons
What’s a Contact force ?
a force that acts between two objects that are physically touching each other.
What’s a non contact force?
forces that act between two objects that are not physically touching each other.
What are examples of contact forces?
Reaction force, Tension, Friction, Air resistance
What are examples of non-contact forces?
Magnetic force, Electrostatic force, gravity
What is an interaction pair?
A pair of forces that are equal and opposite and act on 2 interacting objects
What is weight?
The force acting on an object due to gravity
What is mass?
The amount of matter in an object
What is weight measured in?
Newtons
What is the centre of mass?
The point at which the whole mass of an object is concentrated
How do you measure weight?
Using a newton meter
What is the equation for weight?
Weight = mass X gravitational field strength
What is the equation for work done?
Work done = force X distance moved in the direction of the force
What is the resultant force?
The sum of all the forces acting on an object overall
What does a free body diagram show?
the forces acting on an object
What do the arrows on the free body diagram represent?
The different forces
What do the direction of the arrows on a free body diagram show?
The direction of the forces
What do the lengths of the arrows on a free body diagram represent?
The size/magnitudes of the forces
What happens if all the forces acting on an object give a resultant force of 0?
The forces are balanced and the object is in equilibrium
What is meant by resolving a force?
splitting the force into 2 component forces that are at right angles to each other. The combination of the 2 forces has the same effect as the original single force.
What is work done?
The energy transferred when a force moves an object through a distance
What is elastic deformation?
When an object can go back to its original shape and length after the force has been removed
What is inelastic deformation?
When an object doesn’t return back to its original shape and length when the force has been removed
What are objects that can be elastically deformed called?
Elastic objects
What is the extension of a stretched spring directly proportional to?
The load of the force applied
What is Hooke’s law?
force = spring constant × extension
What is the Limit of proportionality?
The limit of proportionality refers to the point beyond which Hooke’s law is no longer true when stretching a material. The elastic limit of a material is the furthest point it can be stretched or deformed while being able to return to its previous shape.
What happens once a material has gone past its elastic limit?
its deformation is said to be inelastic.
The higher the spring constant….
the stiffer the spring
What is a moment?
The turning effect of a force
What is the equation for a moment?
moment of a force = force × perpendicular distance from the line of action of the force
What is a moment measured in?
newton-metres (Nm)
What do levers do?
They make it easier for us to do work i.e lift an object
Why do levers mean less force is needed to get to the same moment?
Because levers increase the distance from which the force is applied
If an object is balanced, the total clockwise moment about a pivot is equal to…
the total anticlockwise moment about that pivot.
What does a lever consist of?
a pivot, an effort, a load
Why are levers force multipliers?
Because they increase the effect of the force
What are gears?
wheels with toothed edges that rotate on an axle or shaft.
Will a larger gear turn slower than a smaller gear?
Yes
What happens when 2 gears meet?
the teeth must both move in the same direction
The forces acting on the teeth of gears are identical but their what are different?
Their moments
If the driven gear is made larger it will rotate more slowly but with a greater or smaller moment?
a greater moment
If the driven gear is made smaller it will rotate more quickly but with a greater or smaller moment?
smaller
What is pressure?
Force per unit area
What is a fluid?
Substances that can ‘flow’ because their particles are able to move around