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level: 1-3

Questions and Answers List

level questions: 1-3

QuestionAnswer
average speedtotal distance travelled by an object divided by the total time taken
instantaneous speedthe speed of an object measured over a very short period of time
displacementthe distance travelled in a particular direction; it is a vector quantity
vector quantitya quantity with both magnitude and direction
scalar quantitya quantity with magnitude only
velocitythe rate of change of an object's displacement
vector trianglea triangle drawn to determine the resultant of two vectors
resultant vectorthe single vector formed by adding together two or more vectors
accelerationthe rate of change of velocity of an object; the unit is m/s²
constant accelerationwhen the change in velocity of an object is the same in the same time period; sometimes called uniform acceleration
uniform accelerationwhen the change in velocity of an object is the same in the same time period
non-uniform accelerationwhen the velocity of an object changes by different amounts in the same period of time
tangenta straight like that touches a curve but does not cross it at a point
free fallwhen an object accelerates due to gravity in the absence of any other forces such as air resistance
componentthe effect of a vector along a particular direction
Newton's second law of motionresultant force is proportional (or equal) to mass x acceleration/rate of change of momentum
weightthe force on an object caused by a gravitational field acting on its mass
frictionthe name for a resistive force when two surfaces are in contact and tending to slide over one another
centre of gravitythe point where the entire weight of an object appears to act
uniform motionthe natural state of motion of an object-uniform velocity, constant speed and direction
Newton's first law of motionan object will remain at rest or in uniform motion unless acted on by a resultant force
resultant forcethe single force that has the same effect as all of the forces acting on an object
terminal velocitythe maximum velocity reached by an object falling under gravity or accelerated by a constant force
resistive forcea backwards force in the opposite direction to movement caused by friction ot some other viscous force
draga force that resists the movement of a body through a fluid
contact forcethe force perpendicular to a surface when two objects are in contact
upthrustthe force upwards in a liquid or gas caused by the pressure in the gas or liquid
Newton's third law of motionwhen two bodies interact, the forces they exert on each other are equal in size and opposite in direction
base unitsdefined units of the SI system from which all other units are derived
derived unitsunits that are combinations of the base units of the SI system
newtonone newton is the force that will give 1kg mass an acceleration of 1m/s² in the direction of the force
homogenousequations with the same base units on each side are homogenous
massthe quantity of matter which a body contains