physics chapter 2 Flashcards
what is speed
speed is the distance travelled per unit time
which unit can be used to measure speed
metres per second (m/s)
how can we calculate speed
distance divided by time
how can we calculate the average speed
total distance travelled divided by the total time taken
define distance
the total length covered by a moving object regardless of the direction of motion
define displacement
the distance measured in a straight line in a specified direction
what are the characteristics of distance and displacement
distance
- the total length covered by a moving object regardless of the direction of motion
- has magnitude only
- can be measured in km,m,cm and mm
displacement
-the distance measured in a straight line in a specified direction
- has both magnitude and direction
- can be measured in km, m, cm and mm
- refers to the shortest distance and direction of an object from the starting point
what is velocity
velocity is the speed in a given direction. One commonly used unit for velocity is metre per second (m/s)
how do we calculate velocity
displacement divided by the time taken
how do we calculate the average velocity
total displacement divided by the total time taken
what is acceleration
the change in the rate of velocity. It is the amount that velocity changes per unit time
in which unit is acceleration measured
metres per second squared
how do we calculate acceleration
change in velocity divided by time
what do we say when an object is going faster
accelerating
what do we say when an object is slowing down
decelerating
in a speed time graph, how is distance calculated
the area under the graph
in a distance time graph, how is speed calculated
the slope or the graident
in a speed time graph, is is acceleration calculated
the slope or the gradient
what is the acceleration of free fall
In the absence of air resistance, all objects fall with the same acceleration regardless of their mass
what is air resistance
a form of frictional force.
what is the acceleration due to gravity
9.8 m/s
what are the characteristics that air resistance has
- opposes the motion of moving objects
- increases with the surface area of moving objects
- increases with the density of air
- it increases the speed of moving objects
