Download LVI AS Physics Self

LVI AS Physics Self-Study Pack
This self-study pack covers Chapter 8 of the disk and student book. Work through the
assignments given, making use of the book and disk as suggested. It is a good idea
to use the student book as a background reader to give yourself a flavour of the
material.
What does this cover?
This is the work we are going to look at, as given in the specification. The full
specification is available at
http://www.ocr.org.uk/Data/publications/key_documents/AS_ALevel_GCE_Physics_
B_Advancing_Physics_Specification.pdf .
You can access a lot more questions and help from the Advancing Physics
Disk.
1. knowledge and understanding of phenomena, concepts and relationships by describing and explaining
cases of:
(i) the use of vectors to represent displacement, velocity and acceleration;
(ii) the trajectory of a body moving under constant acceleration, in one or two dimensions;
(iii) the independent effect of perpendicular components of a force;
(iv) calculation of work done, including cases where the force is not parallel to the velocity;
(v) power as rate of transfer of energy;
(vi) measurement of displacement, velocity and acceleration;
2. scientific communication and comprehension of the language and representations of physics,
by making appropriate use of the terms:
(i) displacement, speed, velocity, acceleration, force, mass, vector, scalar, power;
by sketching and interpreting:
(i) graphs of accelerated motion, including slope and area below the graph
(displacement–time and velocity–time graphs; acceleration not necessarily constant);
(ii) graphical representation of addition of vectors and changes in vector magnitude and direction;
3. quantitative and mathematical skills, knowledge and understanding by making calculations and
estimates involving:
(i) the resolution of a vector into two components at right angles to each other;
(ii) the addition of two vectors, graphically and algebraically
(algebraic calculations restricted to two perpendicular vectors);
Part 1 Journeys

Read pages 171 – 175 in the student book.

Sketch these graphs – use plain or lined paper but keep them carefully to
discuss with you class at the end of the independent work time.
(a) A velocity-time graph of a feather falling on the moon.
(b) A distance-time graph of a feather falling on the moon.
(c) A speed-time graph of a ball thrown vertically, reaching a maximum height
and then falling back to the ground.
(d) A velocity-time graph of a ball thrown vertically, reaching a maximum height
and then falling back to the ground.
(e) A distance- time graph of a ball thrown vertically, reaching a maximum
height and then falling back to the ground.
(f) A displacement- time graph of a ball thrown vertically, reaching a maximum
height and then falling back to the ground.

Try the ‘quick check’ questions on page 175 – keep them carefully.
Finally, do a bit of revision using these questions:
Question 20S:
Graph paper is needed for some. These questions are all based on the connection
between speed, distance and time.
1.
You are watching a batsman hit a cricket ball. If 0.375 s passes between the
time you see him strike the ball and the time you hear the sound of this, how far from
the batsman are you sitting? The speed of sound in air is 340 m s–1. (The speed of
light is nearly a million times bigger than this, so you see the bat hit the ball more or
less at the instant it occurs.)
2.
A girl diving from a 15 m platform wishes to know how fast she enters the
water. She is in the air for 1.75 s and dives from rest (with an initial speed of zero).
What can you tell her about her entry speed?
3.
An experiment performed on the Moon finds that a feather falls 20.75 m from
rest in 5 s. What is its speed as it hits the Moon's surface?
4.
The sketch graph shown represents the variation in vertical height with time
for a ball thrown upwards and returning to the thrower.
From this graph sketch a velocity–time graph.
5.
In a Tour de France time trial a cyclist is able to reach a top speed of
100 km h–1 by starting from rest and pedalling flat out for a distance of 3 km. If the
rate at which the cyclist's speed changes is uniform, how long will this take?
6.
You are travelling in a car moving at 50 km h–1 (just over the 30 mph speed
limit). What is this speed in m s–1? You have to brake so the car comes to rest
uniformly in 1.4 s, how far will you travel? A cat runs out in front of your car and your
reaction time is 0.6 s. What is the total distance the car will travel before stopping?
7.
A steam traction engine speeds up uniformly from rest to 4 m s–1 in 20 s. It
then travels at a steady speed for 440 m and finally comes to rest uniformly in 10 s
having travelled 500 m in total. Draw a speed–time graph for its motion showing key
values of speed and time. What is the total time for the journey? What is the average
speed for the whole journey?
8.
A tennis ball is dropped from a height of 2 m above a hard level floor, and
falls to the floor in 0.63 s. It rebounds to a height of 1.5 m, rising to its original
position 1.18 s after it was released. Draw a speed–time graph indicating speed and
time at key points of the motion.
Part 2 Maps and Vectors
This is an introduction to vectors – you may think you know about this already but it is
still worthwhile spending time on this.
 Read pages 176 – 181 of the Student Book.
 Try the quick check questions on page 181
 Try these, keeping your answers carefully. The answers can be found on the
disk.
Question 60S: Short Answer
Teaching Notes | Key Terms | Answers
Quick Help
These questions give you practice in adding vectors.
1.
John walks 10 m west followed by 10 m north. What is his displacement from
the starting position, and in what direction?
Two forces act
Forces of 5.0 N and 2.0 N both act on an object.
2.
What is the maximum possible total force?
3.
What is the minimum possible force?
4.
What is the total force if the two forces act at right angles to one another?
A sledge is being pulled at constant speed by a force of 50 N acting at 30° to the
ground.
5.
What is the horizontal component of the force?
6.
If the sledge is moving at a constant speed what is the force of friction
between the sledge and the snow?
7.
What is the vertical component of the pulling force?
Flying in a sidewind
Question 70S: Short Answer
Relative velocities and displacement
In these questions, you have to find the velocity and the displacement of a bird
relative to the ground, when it is actually flying relative to the wind.
A bird flies at a steady speed of 3.0 m s–1 through the air. It is pointing in the direction
due north. However, there is a wind blowing from west to east at a speed
of 2.0 m s–1.
1.
What is the velocity of the bird relative to the ground?
2.
What is the displacement of the bird, relative to its starting point, after it has
flown for 20 seconds?
3.
In what direction should the bird point if it is to travel in a northerly
direction?
Part Three
Just to check that you understand the previous questions, read through pages 182 to
187 and try the quick check section on page 186 – keeping your answers carefully
once again.
Remember – there is much more information on the disk if you need further help with
this material.