Physics P2a revision
difference between velocity and speed
velocity is vector quantity
speed is scalar quantity
what do scalar quantities have
only a magnitude (size)
what do vector quantities have
has a magnitude (size) and a direction
equation for average speed
distance / time
how far would a runner travel in 30 seconds if she travels at a constant speed for 3m/s
90m
a cyclist travels at a constant speed of 5m/s for 1minute, before speeding utp instantly o 10m/s for 10 seconds. how far does the cyclist travel overall?
400m
If a car travelling at a velocity of 10m/s suddenly turns around and continues at the same speed, what is is new velocity ?
-10m/s
what does the length of an arrow represent
the magnitude (size) of a quantity
what does the direction of the arrow represent
the direction of the vector quantiity
what is the difference between a scalar and a vector
a vector has direction and magnitude
3 examples of vector quantities
velocity
force
acceleration
equation for acceleration
change in velocity/ time taken
what is acceleration measured in
metres per second squared
a ball rolling down a hill accelerates uniformly from rest to a velocity of 5m/s in 10 seconds. what is the acceleration of the ball
0.5m/s^2
3 examples of scalar quantities
- temperature
- mass
-energy
what is displacement
the distance an object moves in a straight line from starting point to a finishing point
is displacement vector or scalar quantity
vector quantity
what is distance
how far an object moves
is distance scalar or vector quantity
scalar quantity
when do non contact forces happen
when objects are separated and not touching
examples of non contact forces
gravitational force
electrostatic force
magnetic force
when do contact forces happen
when two objects are physically touching
examples of contact forces
friction
air resistance
tension
if an object travels 4 metres down then 2 metres backwards, what is the distance travelled? what is the objects displacement?
total distance= 6 metres
displacement = 2 metres
what is an interaction pair
set of 2 forces that are equal and opposite, acting on 2 interacting objects
on a line graph how is a constant speed shown
by a straight line
on a line graph how is a stationary object shown
if the line is horizontal
area of a triange
0.5 x base x height
area of a rectangle
base x height
if an object travels 15 metres in 5 seconds, what is the slope of its distance-time graph
3m/s
if an object travels at 10 m/s constantly for 1 minute, how far will it have travelled
600m
a sprinter ran 100m in 9.71 seconds. what was his average speed? 2dp/rounded
10.3
how far would a runner travel in 33 seconds if she travels at a constant speed of 6m/s
198m
how far would a runner travel in 31 seconds if she travels at a constant speed of 4m/s
124m
a ball rolling down a hill accelerates uniformly from rest to a velocity of 26m/s in 14 seconds. what is the acceleration of the ball? 2dp/rounded
1.86 m/s^2
a ball rolling down a hill accelerates uniformly from rest to a velocity of 9m/s in 9 seconds. what is the acceleration of the ball? 2dp/rounded
1m/s^2
if an object is travelling at a velocity of 6ms^-1, then decelerates for 2 seconds at which point its velocity is 2ms^-1 , what is the acceleration of the object?
its -2ms^-2
a ball is initially at rest and travels 9m. the ball travels at an acceleration of 10.7m/s^2. what is the final velocity of the ball? 1dp
1.2 m/s
a car starts at rest and accelerates at a constant rate of 30mph in 10 seconds. what does its velocity-time graph look like?
straight line with a positive gradient
which property of a velocity time graph gives the distance travelled by the car
area
equation for speed
distance/time(taken)
what is mass
measure of amount of matter an object contains
what is inertia
the measure if how difficult it is to change an objects motion
equation for weight
weight = mass x gravitational field strength
what is an objects centre of mass
a single point where all the mass appears to be
when will an object topple
when its centre of mass is located outside its base
what is the resultant force
sum of all forces acting on an object
equation for the resultant force
resultant force= mass x acceleration
if forces act along the same line, the resultant force can be calculated using what equation
forces acting in one direction - forces acting in opposite direction
2 types of deformation
elastic
inelastic
equation for hookes law
spring constant x spring extension
what is the springs constant
how stiff the spring is
how to work out the extension of spring
length of spring with masses - original length of spring
equation for spring extension
force applied / spring constant