# Physics P2a revision - copy x

## 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?

## 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