Unit 2 & 6 Flashcards
Instantaneous Speed
The speed of an object at an instant in time; the rate of change in position with respect to time
Average speed
The average speed of a journey = total distance divided by total time
Acceleration
the rate of change of velocity respect to time
Air Resistance
The transfer of energy into a fluid from an object moving in it
Translational Equilibrium
A body is in translational equilibrium when the sum of all the external forces acting on it equals zero
Newton’s First Law
A body will remain at constant velocity unless acted upon by a resultant external force
Inertia
The property of matter by which it continues in its existing state of rest or uniform motion in a straight line unless that state is changed by an external force.
Newton’s Second Law
The resultant external force acting on a body is proportional to the rate of change of momentum of the body
Newton’s Third Law
When body A exerts a force on body B, body B exerts a force on body A that is equal in magnitude and opposite in direction
Static Friction
the friction when there is no relative movement between the surfaces.
Dynamic Friction
the friction when there is relative movement between the surfaces
Kinetic Energy
the energy an object has because of its motion.
Gravitational Potential Energy
the energy an object has because of its position in a gravitational field.
Elastic Potential Energy
energy stored as a result of the deformation of an elastic object/the work done to stretch the spring.
Work Done
force exerted * distance moved in the direction of the force
Power
the rate of energy transfer
Principle of Conservation of Energy
energy cannot be created or destroyed, only transferred form one form to another.
Momentum
The product of an object’s mass and velocity, measured in kg m s-1
Impulse
The change of an object’s momentum, measured in kg m s-1
Collision
an interaction where momentum transfers.
Principle of Conservation of Momentum
Total momentum of a system is always constant provided no external force acts
Elastic Collision
A collision where kinetic energy is conserved.
Period
the time taken for the object to go round the circle once.
Frequency
the number of times the object goes around the circle each second.
