Definitions Flashcards
(30 cards)
Describe how a scalar is different from a vector.
A scalar quantity (e.g: mass) has only magnitude, while a vector quantity (e.g: velocity) has both direction and magnitude.
Give five examples of scalar quantities.
– Mass
– Volume
– Speed
– Distance
– Density
– (Etc…)
Give five examples of vector quantities.
– Forces
– Velocity
– Displacement
– Pressure
– Acceleration
– (Etc…)
What is meant by the term ‘distance’?
The length between two points.
What is meant by the term ‘displacement’?
Distance with direction.
What is meant by the term ‘speed’?
The rate of change of distance.
What is meant by the term ‘velocity’?
The rate of change of displacement.
What is meant by the term ‘acceleration’?
The rate of change of velocity.
What is meant by the term ‘deceleration’ / ‘retardation’?
The negative of acceleration.
Name the three types of variables in an experiment and what they do.
– Independent variable (The one that changes)
– Dependent variable (The one that is measured)
– Controlled variable (The one that stays the same)
State Newton’s First Law of Motion
Newton’s First Law states that in the absence of unbalanced forces, an object will continue to move in a straight line at a constant speed, or if at rest, stay at rest.
State Newton’s Second Law of Motion
Newton’s Second Law states that a resultant force will cause an object to accelerate and that the acceleration is proportional to the size of the resultant force.
(F = ma)
State Newton’s Third Law of Motion
Newton’s Third Law states that if an object ‘A’ exerts a force on object ‘B’, then object ‘B’ will exert an equal but oppositely directed force on object ‘A’.
What is meant by the term ‘mass’?
Mass is the amount of matter in an object, which is measured in kilograms.
What is meant by the term ‘weight’?
Weight is the acceleration due to gravity on an object (on Earth). For GCSE Physics, it is a constant of 10m/s² or 10N/kg, as it is also considered to be a force.
(For an answer, put: ‘The pull of gravity on a mass.’
What is friction?
Friction is the force produced when two or more materials rub against each other. It is only present if there is motion and will always oppose the direction of motion.
How can friction be reduced?
– Lubrication of moving parts/objects (e.g: oil)
– Smoothing of surfaces (e.g: waxing)
– Reducing the area between the two surfaces (e.g: wheels or balls)
– Use a cushion of air between the two surfaces (e.g: hockey table)
All objects, in the absence of ___ _____, fall at the same ___, regardless of their ___.
All objects, in the absence of air resistance, fall at the same rate, regardless of their mass.
What happens when an object reaches terminal velocity?
The force of air resistance is equal to the object’s weight. Since the forces on the object are now balanced, it will no longer accelerate, so it has reached its final, maximum velocity.
State Hooke’s Law
Hooke’s Law states that the extension of a spring is directly proportional to the stretching force applied to it, provided that the limit of proportionality is not exceeded.
What is meant by the term ‘pressure’?
Pressure is the force acting on unit area.
What is meant by the term ‘centre of gravity/mass’?
The centre of gravity/mass is the point at which all of the mass of an object appears to act.
What is a moment?
A moment is a turning force.
State the Principle of Moments
The Principle of Moments states that when in equilibrium, the total clockwise moment about a point is equal to the total anti-clockwise moment about the same point.
