Mechanics 1 Flashcards
Definition of a vector.
A vector quantity is a quantity with both magnitude and direction.
3 examples of a vector
- Displacement
- Velocity
- Acceleration
Definition of a scalar.
A scalar quantity is a quantity with magnitude but not direction.
3 example of a scalar
- Work
- Energy
- Power
Definition of speed.
Distance / Time
Unit - ms-1
Definition of velocity.
Displacement / Time
Unit - ms-1
Definition of acceleration.
Final velocity - initial velocity / time
v - u / t
Unit - ms-2
State Newton’s Law 1.
A body continues in a state of rest or uniform motion in a straight line unless a resultant external force acts on it.
Definition of friction.
Friction is a force that opposes the relative motion of two objects in contact.
Momentum.
The momentum of a body is the mass multiplied by the velocity. P = M x V , Unit is kg ms-1
State Newton’s Law 2.
When a resultant external force acts on a body the rate of change of the momentum of the body is proportional to this force and takes place in the direction of the force.
Definition of mass.
The mass of a body is a measure of its inertia, i.e its reluctance to change velocity.
Definition of weight.
The weight of a body is the force of gravity acting on the body.
State Newton’s Law 3.
To every action there is an equal and opposite reaction. Action and reaction do not happen on the same body.
Statement of the conservation of momentum law.
When two or more bodies interact in a CLOSED SYSTEM, the total momentum of the bodies before the interaction equals the total momentum of the bodies after the interaction.
Definition of work.
Work is force multiplied by displacement.
Definition of energy.
Energy is the ability to do work. The unit of energy is the joule (J).
Conservation of energy.
Energy cannot be created or destroyed but may be changed from one form to another.
Definition of kinetic energy,
The kinetic energy of an object is the energy it has due to its motion.
Definition of potential energy.
The potential energy of an object is the energy it has due to its position, shape or state.
Definition of power.
Power is the rate at which work is done. This unit of power is the watt (W).
Distance
Half the circumference of a circle = 2πr / 2
What units do we use in leaving cert
Metres, kilograms and seconds.
For linear motion, what adjustment do we make to the equations of motion.
Change a for g (gravity)
