Int1 SN Movement

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Intermediate 1 Physics

Movement

Learning Outcomes

and

Summary Notes

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Learning Outcomes

By the end of this topic you should know

!orces

Describe how to use a Newton balance to measure force.

State that weight is a force and is the Earths pull on an object.

Calculate weight using: weight = mass x !

State that the force of friction can oppose the motion of anobject.

Describe one wa" in which the force of friction can be increased.

Describe one wa" in which the force of friction can be decreased.

State that streamlining reduces the effect of air friction on an

object.

Describe two features of a car which impro#e streamlining.

State that e$ual forces acting in opposite directions on an object

are called balanced forces.

%dentif" situations where the forces acting on an object are

&a' balanced

&b' not balanced.

State that when the forces acting on an object are balanced the

mo#ement of the object does not change.

State that when the forces acting on an object are not balanced

the speed and( or direction of mo#ement of the object changes.

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Speed and acceleration

Describe how to measure a#erage speed.

Calculate a#erage speed using: a#erage. speed = distance(timeDescribe how to measure instantaneous speed.

Describe the term )acceleration.

Moving o"#ects

Describe how the effect of a collision increases with the mass andspeed of the objects in#ol#ed.

State that the change in speed of an object increases with:

&a' the si*e of the force acting

&b' the time the force acts.

State that the range of a ball thrown at an angle is affected b":

&a' the speed of the throw

&b' the angle of the throw.

State that the height a ball rebounds on hitting a surface is

affected b":

&a' the speed on impact

&b ' the material of the surface

&c' the material of the ball.

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!O$%&S

Measuring !orce

+ force can change the direction speed and(or shape of an object.

,orce is measured using a ---------- ---------.

he unit of force is the ------------ &N'.

'eight

/eight is a force. /eight is the pull of the ---------- on an object.

0ass is the amount of matter in an object it is measured in 1ilograms.

2ou can find the weight of an object if "ou 1now the objects mass.

'eight ( 1) mass

Example: ,ind the weight of a 3! 1g child.

/eight = ------ mass

=

= ------ N

he weight of a 3! 1g child is -------- Newtons.

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!riction

,riction is a force that opposes motion. %t acts in the opposite direction

to the mo#ement of an object. he forces of friction can ---------

down or --------- a mo#ing object.

,riction acts when surfaces are in contact with each other.

wo wa"s in which friction can be reduced are:

. --------------------------------------------------

--------------------------------------------------

3. --------------------------------------------------

--------------------------------------------------

wo wa"s in which friction can be increased are:

. --------------------------------------------------

--------------------------------------------------

3. --------------------------------------------------

--------------------------------------------------

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Streamlining

/hen an object mo#es through the air4 the air rubs against the object

causing friction5 this air friction is called ------ ---------------.

Streamlining is when "ou change the ---------- of an object to reduce

air resistance.

/ind tunnels are used to impro#e the streamlining of cars. he shape can

be made li1e a teardrop or an aeroplane wing to reduce air resistance.

hree features of streamlining are:

. --------------------------------------------------

--------------------------------------------------

3. --------------------------------------------------

--------------------------------------------------

6. --------------------------------------------------

--------------------------------------------------6


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Balanced !orces

/hen two forces are the same si*e as each other andact on the same

object but in opposite directions4 the" balance each other. he" are

called -------------- forces.

7n each of the diagrams below draw in an arrow and state its #alue4 so

the forces on each are balanced.

8N

3!N 6!N

Examples of balanced forces

/hen two tug9of9war teams are pulling against each other but neither is

ma1ing an" progress4 the forces applied b" each team must be

---------------.

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8/15

efore s1"di#ers open their parachute the" fall at a

constant speed called their terminal #elocit". his is

because their weight is balanced b" air resistance.

/hen the" open their parachute the" still fall at a

constant speed but much ---------- than before

because the ----- ---------- is much greater

with the parachute open.

/hen an aeroplane is tra#elling forwards4 the air rushing o#er the wings

creates an upward force. /hen the plane is fl"ing le#el4 this upward

force balances the ---------- of the plane

/hat would happen if the upthrust is greater than the weight;

------------------------------------------------------

/hat would happen if the upthrust is less than the weight of the plane;

------------------------------------------------------

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SP&&* +N* +%%&L&$+,ION

Measuring average speed

/e can measure the speed of an object b" measuring the ---------- it

tra#els and the --------- it ta1es to tra#el that distance.

+#erage speeds are usuall" measured o#er ---------- distances or

-------- times.

he a#erage speed can then be found using the following e$uation:

+#erage speed = ---------------

%n this e$uation4 distance must be measured in -----------

and time must be measured in --------------

his gi#es a#erage speed in ----------- per ------------

he distance can be measured using a tape4 trundle wheel or metrestic1.

ime is measured using a stopwatch or sometimes b" an electronic timer.

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Electronic timers are often operated b" light gates. /hen a mo#ing

object cuts the beam of light gate 4 the timer starts timing. /hen the

object cuts the beam of light gate 34 the timer stops timing.

%n the space below4 explain wh" an electronic timer measures more

accuratel" than using a stopwatch.

------------------------------------------------------

------------------------------------------------------

Examples

. + car tra#els a distance of


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Measuring instantaneous speed

2our speed at an" particular point is called the instantaneous speed.

o measure the instantaneous speed of a mo#ing trolle" a light gate is

used. he timer starts when the trolle" cuts the beam and stops when

the trolle" has passed4

he instantaneous speed is calculated using the --------- of the

trolle" as the distance tra#elled and the reading on the timer as the

time. his gi#es the e$uation:

%nstantaneous speed = ---------------------

Example:

+ trolle" is fitted with a card !.!m in length. %f this card passes a light

gate in !.!38s4 what is the instantaneous speed of the trolle";

%nstantaneous speed = ------------ = ------- = m(s

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+cceleration

+cceleration is the change in ---------- of an object in one -------.

%f an object is getting faster4 its speed increases it is ------------.

%f an object is getting slower4 its speed decreases it is -----------.

%ar Performance

Car manufacturers often state a #alue for their cars acceleration to

indicate its performance. he usual performance figure $uoted is the

time in seconds it ta1es for the car to increase its speed for ! to >!

m.p.h. he shorter the time4 the higher the acceleration.

he table below shows some performance #alues.

0a1e of car %ncrease in speed ime &s'

0ini

?ol#o

,ord

@aguar

! >! mph

! >! mph

! >! mph

! >! mph

!.8

A.>

B.

>.

/hich of these cars has the greatest acceleration; ---------------

Explain "our choice

----------------------------------------

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------------------------------------------------------

MO-IN. BO*I&S

+ B

%ollisions

/hen an object has its speed changed b" another object we sa" the two

objects -----------.

Suppose object + is mo#ing and collides with object .

he speeds of both mo#ing objects will be change b" this collision.

he change in speed of the colliding objects is greater when:

a' he objects are mo#ing ----------- before the collision

b' he objects ha#e a ---------- mass.

c' he forces between the objects act for a ------- time.

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,he range of a "all

/hen an object is thrown or fired hori*ontall"4 it follow a

cur#ed path due to the force of -------------. he

hori*ontal distance tra#elled is called the

-------------.

he range of a ball is increased b":

a' -------------- the speed the ball is thrown

b' -------------- the angle of the throw.

/eight of re"ound

/hen a ball bounces it loses some of its energ" so it ne#er rebounds to

the same height. + ball dropped from B!cm ma" rebound to 8!cm4 but it

will ne#er rebound to B!cm again.

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ebound height of an object will be greater if

a' the speed on impact is -------------

b' the surface it hits is --------------

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