P2.2 Flashcards
contact force
a force that only acts when objects are in contact
drag
a force that acts opposite to the direction of motion of a body
elastic collision
a collision in which kinetic energy is conserved
equilibrium
an object is in equilibrium if all the forces cancel – the resultant force is zero
force arrow
a way to model forces
free body diagram
a diagram that shows the forces acting on a single object
friction
a contact force. It occurs because the atoms that make up the surfaces interact when rough surfaces slide over each other
inelastic collision
a collision in which kinetic energy is not conserved
Law of Conservation of Momentum
In any interaction of collision, the momentum before the collision = momentum after
momentum
mass × velocity
net force
the force when two or more forces are added together as vectors
newton-metre (Nm)
the unit of work, equivalent to the joule. It is also the unit for a moment
Newton’s First Law
the motion (speed and direction) of an object does not change when the resultant force is zero
Newton’s Second Law
if the resultant force is not zero the motion of an object (speed or direction) changes
Newton’s Third Law
forces come in pairs: the force of X on Y and the force of Y on X
