Topic 5 - Forces Flashcards
(33 cards)
Acceleration
The rate of change of velocity. It can be calculated from the
gradient of a velocity-time graph.
Braking Distance
The distance a vehicle travels under the braking force. This
can be affected by adverse road and weather conditions as well as the condition
of the vehicle.
Atmosphere
The thin layer of air surrounding the Earth, which gets less dense
with increasing altitude.
Centre of Mass
The single point through which the weight of the object can be
said to act.
Changes of Momentum
When a force acts on a moving object, or one an
object that has the ability to move, a change of momentum will occur. The
force is equal to the rate of change of momentum.
Conservation of Momentum
The total momentum of a system before an
event is always equal to the total momentum of the system after the event.
Contact Forces
A force that occurs when objects are physically touching.
Displacement
A measure of how far an object moves in a given direction. It is
the straight line between the starting and finishing points and is a vector quantity.
Distance
A measure of how far an object moves, that does not depend on
direction and is therefore a scalar quantity.
Elastic Deformation
Non-permanent deformation which allows the object to
return to its original shape when the deforming forces are removed.
Elastic Limit
The force beyond which an object will no longer deform elastically,
and will instead deform plastically.
Equilibrium
An object is in equilibrium if the resultant force and resultant moment
are both equal to zero.
Floating
An object will float if the volume of liquid it displaces has a greater
weight than that of the object itself. The upthrust acting on the object is
greater than its weight.
Fluid
A liquid or gas.
Forces
A push or pull that an object experiences due to the interaction with
another object. Force is a vector quantity.
Inertia
The tendency of an object to remain in its same state of uniform
motion or rest.
Inertial Mass
A measure of how hard it is to change an object’s velocity. It is
defined as the ratio of force over acceleration.
Limit of Proportionality
The point beyond which the extension of an elastic
object is no longer directly proportional to the force applied to it.
Moment
The turning effect of a force, equal to the product of the magnitude of
the force and the perpendicular distance from the pivot to the line of action of the
force.
Newtonmeter
A calibrated spring-balance used to measure weight.
Newton’s First Law
If a stationary object’s resultant force is zero, the object will
remain stationary. If a moving object’s resultant force is zero, the object will
continue to move at the same speed, and in the same direction.
Newton’s Second Law
An object’s acceleration is directly proportional to the force applied to it, and inversely proportional to its mass.
Newton’s Third Law
The forces that two objects exert on each other when they
interact are equal and opposite.
Pressure in a Column
The pressure in a column of liquid is equal to the product of the liquid’s density, the height of the column and the gravitational
field strength.
