6.5 Forces Flashcards
(28 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
Centre of Mass
The single point through which the weight of the object can be
said to act
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
Elastic Potential Energy
The energy stored in a spring when it is stretched or compressed, due to the work done on the spring by the deforming force
It is equal to the work done as long as the object does not plastically deform
Equilibrium
An object is in equilibrium if the resultant force and resultant moment are both equal to zero
Forces
A push or pull that an object experiences due to the interaction with another object
Force is a vector quantity
Limit of Proportionality
The point beyond which the extension of an elastic object is no longer directly proportional to the force applied to it
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
Non-Contact Forces
A force that occurs when objects are physically separated
Plastic Deformation
Permanent deformation which means the object will no
longer return to its original shape when the deforming forces are removed
Resultant Force
The single force that can replace all the individual forces acting
on an object, and have the same effect
Scalar Quantities
Quantities that only have a magnitude, not a direction
Speed
A scalar quantity that is a measure of the rate of increase of distance
Spring Constant
A measure of a spring’s stiffness, which is the constant of
proportionality for a spring’s extension
The higher the spring constant, the smaller the extension is for a given force
Stopping Distance
The sum of the thinking and braking distances
Thinking Distance
The distance a vehicle travels during the driver’s reaction
time
Typical human reaction times are in the range of 0.2-0.9 seconds
This reaction time may be affected by tiredness, drugs or alcohol
