AQA AS Physics Unit 2 Revision

HideShow resource information
  • Created by: S Satish
  • Created on: 18-04-13 17:04
Preview of AQA AS Physics Unit 2 Revision

First 529 words of the document:

Materials
What is density?
This is the mass per unit volume measured in kgm3
How do you measure the density of a regular solid?
This mass is measured using a top balance
The dimensions are measured using vernier callipers or a micrometer
The volume is calculated using 4/3 x pi x r^3 for a sphere or ¼ x pi x d^2 x h
How do you measure the density of an irregular solid?
The mass is measured using a top balance
The object is immersed on a thread in liquid in a measuring cylinder
The increase in liquid level is observed and this is the object's volume
What is tension in a string?
This is the pull in the string and it is equal and opposite to the force needed to stretch a spring.
What is Hooke's Law?
The force needed to stretch a spring is directly proportional to the extension of the spring from its natural length.
F = k x delta L (k is the stiffness constant and if k is greater the spring is stiffer)
What are the equations for springs in parallel?
The position of the weight is adjusted along the rod to make the extensions of both strings the same.
Since the weight is supported by both springs W= F1 + F2 = k1 x delta L + k2 x delta L
W= k x delta L
Dividing through by delta L means that k = k1 + k2
The spring constant is both spring constants added together
What are the equations for springs in series?
The tension in both springs is the same and equal to W but their extensions are different
Delta L1 = W / k1 and delta L2 = w/k2
L = L1 + L2 so W/ k = W/k1 + W/k2 and 1/k = 1/k1 + 1/k2
What energy is stored in a stretched spring?
Elastic potential energy is stored in a stretched spring and if the spring is suddenly released, this energy is suddenly
converted to kinetic energy of the spring. Energy = area under graph = ½ x F x delta L = ½ x k x delta L^2
What is the elasticity of a solid material?
The elasticity of a solid material is its ability to regain its shape after it has been deformed or distorted and the forces that
have deformed it have been released.
What is the difference between tensile and compressive deformation?
Deformation that stretches an object is tensile whereas deformation that compresses as object is compressive.
How can we test how easily materials stretch?
The material in each case is held at its upper end and loaded by hanging weights at its lower end
A set square or pointer attached to the bottom of the weights may be used to measure the extension of the
material
The weights of the loads are increased in steps then decreased to zero
The extension of the strip of material for each load is its increases in length from its unloaded length

Other pages in this set

Page 2

Preview of page 2

Here's a taster:

Tension = weight of load
What type of graph does a steel spring give?
This gives a straight line through the origin.
What type of graph does a rubber band give?
A rubber band at first extends easily when it is stretched, however when it becomes full stretched it is difficult to stretch
further when it has been lengthened considerably.…read more

Page 3

Preview of page 3

Here's a taster:

What happens beyond the point P?
The line curves and continues beyond the elastic limit E to the yield point where the wire temporarily weakens.
What is the elastic limit?
This is the point beyond which the wire is permanently stretched and suffers plastic deformation.
What happens beyond y2?
A small increase in stress causes a
large increase in strain as the material of the wire undergoes plastic flow.…read more

Page 4

Preview of page 4

Here's a taster:

What is strain energy?
This is the work done to deform an object (area under the line of a forceextension graph)
What is the strain energy for a metal wire/spring?
Provided the limit of proportionality is not exceeded, to stretch a wire to a certain extension the work done is ½ tension x
extension because the elastic limit is not reached and the work down is stored as elastic energy in the wire.…read more

Page 5

Preview of page 5

Here's a taster:

How can we locate the centre of mass of a metre rule?
We can do this by balancing it on a horizontal knife edge using a known weight whose position needs to be adjusted
gradually until the rule is exactly horizontal.
What is a couple?
This is a pair of equal and opposite forces acting on a body but not along the same line.
What is a torque?
This is the moment of a couple calculated by force x perpendicular distance apart.…read more

Page 6

Preview of page 6

Here's a taster:

When one end of a slinky is moved back and forth repeatedly, each forward movement causes a compression wave to
pass along the slinky as the coils push into each other and each backward movement causes the coils to move apart so a
rare faction (expansion) wave passes along the slinky.
What are transverse waves?
These are waves in which the direction of vibration is perpendicular to the direction in which the wave travels.…read more

Page 7

Preview of page 7

Here's a taster:

This is the number of cycles of vibration passing of a particle per second or the number of complete waves passing a point
per second.
What is wave speed?
C= f x lambda
What is phase difference?
This is the fraction of a cycle between the vibrations of two vibrating particles, measured in radians or degrees.…read more

Page 8

Preview of page 8

Here's a taster:

These are waves that travel through a substance or through space if electromagnetic. These waves combine at fixed points
of no displacement (nodes) along the rope and at each node, the two sets of waves are always 180degrees (pi radians) out
of phase so they cancel each other out.…read more

Page 9

Preview of page 9

Here's a taster:

The amplitude of vibration is 0 at the nodes so there is no energy at the nodes and the amplitude of vibration is a maximum
at the antinodes so there is maximum energy at the antinodes. Since the nodes and antinodes are at fixed positions there
is no energy transferred in a freely vibrating stationary wave pattern.…read more

Page 10

Preview of page 10

Here's a taster:

The crest reverses its phase when it reflects on the fixed end and travels back along the string as a trough. When it
reaches the vibrator it reflects and reverses again. It is travelling away from the vibrator as a crest. If this crest is reinforced
by a crest from the vibrator, the wave's amplitude is increased.…read more

Comments

Miss Meera J

First Glance - Very detailed!!!

Similar Physics resources:

See all Physics resources »See all resources »