P5 - Forces Flashcards
Define a Force
A force is a push or pull that acts on an object due to the interaction with another object.
Define contact force
The objects are physically touching
Define non-contact force
The objects are physically separated
Name 4 examples of contact forces
Friction
Air resistance
Tension
Normal contact force
Name 3 examples of non-contact forces
Gravitational force
Electrostatic force
Magnetic force
Define scalar quantity and give examples
Scalar quantities have magnitude only.
(Mass, Time, temperature, speed, energy, distance)
Define vector quantity and give examples
Vector quantities have magnitude and an associated direction.
(Displacement, weight, force, velocity, acceleration, momentum)
When using an arrow to represent a vector quantity, what does the length and direction of the arrow represent?
Length - represents magnitude.
Direction - represents the direction of the vector quantity.
Define weight
The force acting on an object due to gravity.
Define centre of mass
The weight of an object can be considered to act at a single point.
What is the equation to calculate the weight of an object?
Weight (N) = mass (kg) x gravitational field strength (N/kg)
The weight of an object is (…) to the mass of the object
Directly proportional
Define resultant force.
A number of forces acting on an object may be replaced by a single force that has the same effect as all the original forces acting together.
Define work done.
Work is done on an object when a force causes an object to move through a distance.
What is the equation for work done by a force on an object?
Work done (J) =
force (N) x distance (m) (moved along the line of action of the force)
What does work done against the frictional forces acting on an object cause?
A rise in the temperature of the object
Describe elastic deformation.
Elastic materials will always return to their original length or shape if we take away the forces acting on them.
Describe inelastic deformation.
When inelastic materials are stretched, they do not return to their original length or shape when the forces are removed.
What is the equation for calculating the force needed to stretch or compress an object?
Force (N) = spring constant (N/m) x extension (m)
Describe the energy transfers taking place when an elastic object undergoes stretching, compression or bending.
When we stretch or compress an elastic object, we are using a force to do work.
Elastic potential energy is stored in the object.
The work done is equal to the elastic potential energy, however this is only true if the object is not inelastically deformed.
