Download Physics – BC Revision Guide

P2 exam questions
Topics:
1.Motion
2.
3.
4.
5.
6.
7.
Forces
Work, energy and momentum
Current electricity
Mains electricity
Radioactivity
Energy from the nucleus
http://www.gcsescience.com/pfm48.htm
Chapter 1- motion
1. Pushing, pulling, squeezing and stretching. What are they all examples
of? 1. The effects of forces
2. Forces can change the shape of an object, change its speed or
direction. True or false?2. True
4. Objects that are elastic can be
3.
N
3. What are the units for force?
pushed or pulled out of shape but
4. Describe how elastic objects work? will regain their original shape when
As one increases, the other one
5. What does directly proportional5.10.
mean?
released.
6.
7.
8.
9.
speed=
Velocity
Acceleration
m/s
m/s
distance/time
is the
means
samechange
as speed
in in a
2at the same rate.
increases
11.
m/s
6. How do you calculate speed?
way, butover
velocity
it is time
in a particular
taken. Itdirection.
is
7. What is velocity?
and
So 12.
calculated
thed/t
definition
as: v/tis: speed in a given
8. What is acceleration?
direction
Change
in velocity/time taken
9. What are the units for velocity?
10. What are the units for speed?
11. What are the units for acceleration?
12. What are the two types of motion graphs we need to know about?
Questions
1.
Jane drives at an average speed of 45 mph on a journey of 135
miles. How long does the journey take?
135 miles ÷ 45 mph = 3 hours
2.
Chris cycles at an average speed of 8 mph.
If he cycles for 6½ hours, how far does he travel?
8 mph × 6.5 hours = 52 miles
3.
Nikki has to travel a total of 351 miles. She travels the first
216 miles in 4 hours.
(a) What is her average speed for the first part of the
journey?
216 miles ÷ 4 hours = 54 mph
4.
Her average speed is the same for the whole of her journey.
(b) How long does the whole journey take?
351 miles ÷ 54 mph = 6.5 hours
Questions
1. Jim travels 45 miles at 15 mph.
How long does it take him?
2. Jemimah walks at 4 mph for 2½ hours.
How far does she walk?
3. Jenny drives at a constant speed. In the
first three hours she travels 81 miles.
How far will she have travelled after 5
hours?
speed = distance/time
evidence of distance = speed × time or 4
× 20
gains 1 mark
but
80
gains 2 marks
units m
for 1 mark
35 (m)
shallowest slope/ gradient
12m/s ÷ 3s = 4 m/s2
Adding the units will give you
the extra mark
1.25 m/s 2
60
5 ½ hours
A – B constant speed
do not accept pace for speed
B – C (has accelerated) to a higher
(constant) speed
C – D goes back to original / lower
(constant) speed
Constant speed
Accelerates to higher constant speed
constant speed in a straight line
do not accept normal speed
do not accept it is stopped / stationary
Goes down
20 (m/s)
first statement must be accelerated
if it just accelerated then decelerates award 2 marks
1
final statement must be stationary
1
interim statement decelerates
1
C and D or D and C
streamline position streamline clothes
3
(gains 1 mark)
m/s2 (gains 1 mark)
deceleration / speed decreasing / slowing down /
negative acceleration
constant speed / steady speed not constant motion /
slow speed
acceleration / speed increasing / speeding up
acceleration / speeding up
constant / steady velocity
walking at constant speed
P2 exam questions
Topics:
1. Motion
2. Forces
3. Work, energy and momentum
4. Current electricity
5. Mains electricity
6. Radioactivity
7. Energy from the nucleus
http://www.gcsescience.com/pfm48.htm
Chapter 2- forces
1. What is resultant force?
14. Zero
resultant
andfor
an object
is travelling
at a steady speed.
2. force
What
are force
the
units
resultant
force?
15. The
that
resists
the motion
of
an
object
through
a gas and liquid is called
1. downwards
Overall force
At the
start,
the
object
accelerates
because
of
weight.
There
is no
16.
Hooke's
Law
states:3.is What
is the
resultant
force
ofits
a 4N
force
and awhen
3Nits
force
acting
in the
drag.
17.
It
an
object
that
doesn’t
regain
original
shape
the
forces
deforming
air resistance.
There is a resultant force acting downwards.
2. N- as it is a force (never
samemoving
direction?
For
objects
through air sometimes instead of drag the term air resistance
it
are
removed.
As
gains
the object’s
stays
same,
but
the
airexam
resistance
it
put
‘n’ in
the
or you on
wont
theitextension
is proportional
toweight
the force
force
4.
In speed,
what
direction
does
the
ofthe
weight
always
act?
is used.
As
an object
moves
through
air, the
gas
molecules
in
the air push against
increases.
There
is
a resultant
force
acting
downwards.
mark
3.
inthe
theforce
same direction
as
the is
two
forces
the
spring
will go
back
to
its7N
original
length
when
theget
force
removed
5. What
units
for
the surface
ofare
thethe
moving
object
resultingweight?
in friction between the gas molecules in
Eventually,
the
object’s
weight
is balanced
by the air resistance. There is no
so long
as
we
don't
exceed
the
elastic limit.
6. and
How
do
you calculate
4. Downwards
the air
the
surface
of theforce?
moving object.
resultant
forceare
andthe
theunits
object
a steady speed,
called
terminal
So
basically:
5. N- as
it isthe
a force
7. What
forreaches
mass?
The amount
of drag
encountered
depends
on
the
following:
6. Mass and
(kg) wires.
x accelertation (m/s2)
velocity.
"Hooke's
Law"
is
about
stretching
springs
8. What are units for acceleration?
Shape
What
droptoa feather
a
coin together? The feather and the coin
When9.happens
weHow
apply
ayou
force
a spring,and
it kg
stretches.
7.
isifweight
An object
with
smoothcalculated?
lines will allow the8.air
to2 flow over it more easily reducing
m/s
have
the
same
surface
area,
so
when
they
begin
to fall
If
weroughly
apply
double
the
force,
it
stretches
twice
as
much,
sothey
long have
as weabout
don'tthe
10. What
gravitational
field and
strength
Earth?
the drag.
This is
is the
known
as streamlining
is whyonobjects
built for speed such as
same
airit.
resistance.
9. Mass
x gravitational field strength
over-do
How
do you
calculate
stopping
distance?
racing11.cars
have
smooth
bodies.
As the
itsdistance
air resistance
it soonbraking
balances
the weight
10.
11.increases
10
Stopping
N/kg until
distance=
distance
+
12.feather
How is falls,
braking
increased?
Speed
12.
Bad
weather
conditionse.g.
of the13.
feather.
The feather
now falls
at
velocity.
But
thinking
distance
13.itsIfterminal
the
driver
is tired
orthe coin is much
How is thinking
distance
increased?
Drag increases
with speed.
icy roads
heavier,
so
it has
to travelvelocity?
quite fast before
is large
to
ORunder air
theresistance
influence of
drugsenough
or
14.
What
is
terminal
Area
balance
weight.
In down,
fact, it
probably
hits
the ground
before
reaches its
alcohol
Bad
condition
the
car-ite.g.
15.its
Weight
goes
drag
goes….?
The larger
the area
of contact
the
more
drag
it willof
experience.
terminal
velocity.
worn out brake pads or worn
16. What
is Hooke’s law?
The type
of fluid
out tyres
What
is an drag
inelastic
object?
There17.
will
be more
in a liquid
compared
to a gas as the molecules are a lot
ReducingAspeed
amount
it uses
to travel a particular
closer18.
together.
stonereduces
will fall the
much
fasterofinfuel
air than
in water.
distance. What is this called?
Work out the
resultant
forces (include
the direction
of the force)
gravity
accelerates
friction
falls at a steady speed
53
50N
Weight= mass x gfs
= 0.4 x 10
= 40N
a) (i) the pushing force balanced by the
friction
accept the pushing force equals friction or
pushing force is too small or frictional force is
too great
1
(ii) any two from
an unbalanced force acts on the model bus
the model bus moves
in same direction as pushing force
accept forwards
and will speed up
1500N
Forwards/acceleration
90 (Y)
Has the biggest mass
Mass and
Speed
This is because the equation for kinetic energy is : 1⁄2 × mass × speed2
(i)
0.6
allow 1 mark for correct substitution
2
newtons
accept N
zero
accept nothing
speed is zero
accept not moving
(i)
1
(ii)
1
the time taken to stop
the force on
P2 exam questions
Topics:
1. Motion
2. Forces
3. Work, energy and momentum
4. Current electricity
5. Mains electricity
6. Radioactivity
7. Energy from the nucleus
9. All moving objects have
kinetic energy. The kinetic
energy
an object
has momentum
13. As long as no external forces are acting on the objects
involved,
the total
depends
on its:
stays the same in explosions and collisions. We say that
momentum
is conserved.
Mass
Two railway carriages collide and move off together. Carriage
a mass of 12,000 kg and
4. Friction isAanhas
opposing
moves
5 m/sdoes
before
the collision.
a mass
of 8,000 kg and is stationary
Speed
1. Work
1. atWhat
energy
allow usCarriage
to do? B has
force.
When
two surfaces
before
the
collision.
What
is
the
velocity
of
the
two
carriages
after
the
collision?
2.
Joules
6.
The
energy
stored
in an2
KE=
½
x
mass
x speed
2. What are the units for energy? 3. Joules
slide
past
each the
other,
the
Step 1 – work out the total momentum before the
event
(before
collision):
object
because
of
its
3. What are the units for work?
p the
=between
mforce
×Earth’s
v xthem
5.interaction
Work12.
done=
p = m × v8. The rate of transfer of
position
in
4. What
is friction?
produces
a force300
of friction.
Momentum
of carriage
A before
= 12,000 × 5 = distance
60,000
kgmoved=
m/s
x 8=
energy.
The more
powerful
gravitational
field.
5.
What
is
the
work
done
on
an
object
if
a
force
of
300N
moves
it a
Momentum
of carriage the
B before
= 8,000
kg m/s
J.P= momentum (kg m/s)
an appliance,
faster
it × 0 = 02400
7. Thekgacceleration
distance
of
8m?
M= massdue
(kg)to
Total momentum
before
= 60,000
m/s.
11.
A moving
object
has +P=0 = 60,000
transfers
energy.
PET=
gravity.
On Earth
it
iscollision):
What
energy?
Step6.2 momentum.
– work is
outgravitational
the
total
after
the event
(after
the
V=
velocity
(m/s)
This
ismomentum
thepotential
E/T
15.
Because
momentum
conserved,
total
momentum
10N/kg.afterwards = 60,000 kg m/s
7. tendency
What
is gravitational
field
ofis the
object
to strength?
Seatbelts
Step8.3 How
– workdoout
thecalculate
after the event (after the collision):
you
power?
keep
moving
intotal
themass
same
Airbags
Total
= mass
of carriage
A +and
mass
of carriage
= 12,000 + 8,000 = 20,000 kg
9. mass
What
is kinetic
energy
how
can it beB calculated?
direction.
It
is
difficult
to
Step
4 – work
out new velocity:
Child
car
seats
14.
10.
What
is
elastic potential
the
of energy?
p =The
m × change
vcar
... so
...designed
v = pdirection
÷ m so that
Crumple
zones
is
the structure of the car
11.
What
is
momentum?
movement
of
an
object
with
Velocity
(after
the
collision)
= 60,000The
÷ 20,000 = 3 m/s
will
give
way
during
a
collision.
12. aHow
momentum be calculated?
lot can
of momentum.
metal
of
the
car
will dent,
bend and
foldanduring
a collision
13. What is the total
momentum
after
explosion
equal to?
which
increases
the
amount
of
time
it
takes
the
car
to stop.in
10. stored energy
14. What is a crumple zone?
The
partsexamples
of the car
do this
stretched or squashed
15. Give
of that
car safety.
(the front and the back) are called crumple
zones.
objects
Chapter 3- work, energy and
momentum
Work, energy and momentum
• Kinetic energy= 1⁄2 × mass × speed2
• Momentum means the movement of
something. The bigger the MASS or the
VELOCITY of something, the harder it
is to stop, so it has MORE
MOMENTUM!
each passenger has a different mass
Remember, KE= 1⁄2 × mass × speed2
gravity
33750J
KE = 1/2m (v-u)2
=300/2 x (18-3)2
= 150 x 152
=150 x 225
=33750J
3 m/s2
2850N
friction/air resistance increases with
speed;
till frictional = max forward force;
then force/acceleration is zero
for 1 mark each
alternative limitation for safety
10800kgm/s
allow 1 mark for correct substitution i.e.
900 × 12
Y
accept the one in the middle
accept 90
1
has the biggest mass
1
210 kgm/s
allow 1 mark for correct substitution i.e.
35 × 6
mass
do not accept weight
1
speed
accept velocity
1
Weight = mg
= 0.06 x 10
= 0.6 N
4 (m/s)
1 mark for correct transformation of
either equation
1 mark for correct substitution with or
without transformation
1 mark for correct use of 0.6N
max score of 2 if answer is incorrect
momentum (change in) = mass × velocity
(change in)
accept ... speed
momentum = mass × velocity
accept … × speed or any transposed
version
either
the momentum in a particular direction after (the
collision) is the same as the
momentum in that direction before (the collision)
or total momentum after (the collision) equals the
total momentum before
(the collision) (2)
explosion(s)
or (action of a) rocket (motor(s))
or (action of a) jet (engine)
or firing a gun
momentum = mass velocity or any
correctly transposed version
Total momentum (of a system of bodies)
remains constant
accept momentum before (a collision) =
momentum after (a collision)
rotate the compressor
zero
speed is zero
A
largest mass or weight
first statement must be accelerated
if it just accelerated then decelerates
award 2 marks
1
final statement must be
stationary
1
interim statement decelerates
direction indicated
accept to right or + or – or arrow drawn on diagram
1
300
1
kg m/s or Ns
1
smallest mass
any evidence of: momentum = mass ×
velocity (words, symbols or numbers)
appropriate re-arrangement mass as
0.05kg
each gains 1 mark
but 800
gains 4 marks
M = mv m × v sufficient
= 1500 × 8
= 12 000 kgm/s or Ns
not m × s, mass × speed
P2 exam questions
Topics:
1. Motion
2. Forces
3. Work, energy and momentum
4. Current electricity
5. Mains electricity
6. Radioactivity
7. Energy from the nucleus
Chapter 4- current electricity
1. Draw as many electrical symbols as you can remember.
2. How does an insulator become
negatively
charged?
Electrons
deposited
on surface
Repel
each
other
3. What happens when two negatively charged objects come close
together?
4. How do you calculate current? Charge ÷ time
5. What are the units for current?Ampere (amp)
Opposition to current flow
6. What is resistance?
7. How do you calculate potential Vdifference?
=IR
voltagedifference?
8. What is another term for potential
9. State what Ohm’s law is. V = I R
10. Sketch an LDR graph.
11. Sketch a thermistor graph.
12. Sketch a bulb graph.
13. What is the difference between a series and a parallel circuit?
Series = current same in all devices
Parallel = more than one current path
Current electricity
• Voltage means push. But in science, we can also say
potential difference.
• The voltage of a cell is 1.5V
• The voltage of mains electricity is 230V
• Circuits transport electrons around them (a
current) when there is a push (a voltage).
Otherwise, nothing happens.
• Copper wires are used because they are good
conductors of electricity.
• Series circuit- the current is the same (so the
voltage is shared- think about bulbs getting
dimmer).
• Parallel circuits- it’s all the opposite.
J
1.5 x 4= 6
a)
circuit symbol for a lamp correct
accept
accept any standard of drawing providing circuit would work
1
circuit symbol for a cell correct
1
2 lamps drawn in parallel with 3 cells
polarity of cells must be correct (+ to –) but cells may be either way around