Download Year 11 General Physics quiz

• Motion and Forces
• Heat and cooling
• Electricity
How many significant figures?
 2.00 × 103
 0.00045
 0.1900
How many significant figures?
 2.00 × 103
3
 0.00045
2
 0.1900
4
Scalar or vector?
Force
Speed
Displacement
Distance
Mass
Work
Acceleration
Scalar or vector?
Force
Vector
Speed
Scalar
Displacement
Vector
Distance
Scalar
Mass
Scalar
Work
Scalar
Acceleration
Vector
Use this convention
Up = +
Left = -
Right = +
Down = -
Motion
 You stand on top of a cliff and drop a ball.
What is the sign of the ball’s;
a)Acceleration
b)Velocity
c) Displacement
Motion
 You stand on top of a cliff and drop a ball.
What is the sign of the ball’s;
a)Acceleration
b)Velocity
c) Displacement
-
Motion
 You throw a ball vertically upwards.
While it’s moving upwards, what’s the sign of it’s;
a)Acceleration
b)Velocity
c)Displacement
Motion
 You throw a ball vertically upwards.
While it’s moving upwards, what’s the sign of it’s;
a)Acceleration
b)Velocity
c)Displacement
+
+
Newton’s Laws of Motion
 What is Newton’s first law of motion?
Newton’s Laws of Motion
 What is Newton’s first law of motion?
Every object in a state of uniform motion tends to
remain in that state of motion unless an external
force is applied to it.
Newton’s Laws of Motion
 What is Newton’s second law of motion?
Newton’s Laws of Motion
 What is Newton’s second law of motion?
The relationship between an object's mass m, its
acceleration a, and the applied force F is F = ma.
Newton’s Laws of Motion
 What is Newton’s third law of motion?
Newton’s Laws of Motion
 What is Newton’s third law of motion?
For every action force there is an equal and
opposite reaction force. Forces act in pairs.
What are the equations?
 Force:
 Momentum:
 Kinetic energy:
 Gravitational Potential energy:
 Work:
 Power:
What are the equations?
 Force: F = ma
 Momentum: p = mv
 Kinetic energy: KE = 0.5mv2
 Gravitational Potential energy: PE = mgh
 Work: W = Fs = ∆E
 Power: P = E/t
Force graph – what is the acceleration?
Force (N)
Mass (kg)
Force graph – what is the acceleration?
Force (N)
a = F/m therefore,
a = gradient (+)
Mass (kg)
Heat, Temperature and Internal energy
 Define:
1.
Heat
2. Temperature
3. Internal energy
Heat, Temperature and Internal energy
Heat
Defined as the transfer of energy across a boundary
due to a temperature difference. It is incorrect to say
an object contains “heat energy”, it is correct to say
“internal energy”
Heat, Temperature and Internal energy
Temperature
A measure of how hot or cold something is. Defined
from the average kinetic energy of atoms and
molecules.
Heat, Temperature and Internal energy
Internal energy
Defined as the energy (kinetic and potential)
associated with the random, disordered motion of
atoms molecules. Also known as ‘invisible’ energy.
 Objects A (metal) and B (plastic) are two at the same
temperature and have the same mass.
A
B
If 100J of internal energy is removed from each object
(A and B), will they be at the same temperature?
If 100J of internal energy is removed from each object
(A and B), will they be at the same temperature?
No, because they will have a different specific heat
capacities.
Metal has a lower specific heat value which makes it
more sensitive to heat transfer.
So which object will have the
higher temperature?
Plastic
B
How did this happen?
Thermal expansion
 As the temperature of a liquid or solid increases, the
molecules vibrate faster and occupy more space.
 This results in a volume increase known as thermal
expansion, thus the rails bent.
Accommodating thermal
expansion
Equations
 Equation for energy associated with temperature
change of an object?
 Equation for energy associated with phase change?
Equations
 Equation for energy associated with temperature
change of an object?
Q = mc∆T
 Equation for energy associated with phase change?
Q = mL
Equations
 From Q = mL, there are 2 different L values can that be
used.
1. Lf = Latent heat of fusion (solid-liquid)
2. Lv = Latent heat of vapourisation (liquid-gas)
Heat transfer
 For each case, how does heat get transferred?
Table to hand
2. Saucepan to egg in boiling water
3. Sun to Earth
1.
Heat transfer
 For each case, how does heat get transferred?
1. Table to hand:
Conduction, direct contact
2. Saucepan to egg in boiling water:
Convection, convection currents circulating in water
3. Sun to Earth:
Radiation, no medium in space
Why?
Static electricity
 Rub plastic comb with cloth
 Electrons transfer from cloth to comb
 Comb is negatively charged
 Comb brought near neutral paper and attracts positive
charges in paper
What is the direction of a) electron flow? and
b) current?
-
-
Series and parallel circuits
6V
6V
Series circuit
For each bulb, R = 2Ω
1. Voltage through each
globe?
6V
Series circuit
For each bulb, R = 2Ω
1. Voltage through each
globe? 6/2 = 3V
6V
Series circuit
For each bulb, R = 2Ω
1. Total resistance?
6V
Series circuit
For each bulb, R = 2Ω
1. Total resistance?
R(total) = R + R
= 2+2
=4Ω
6V
Parallel circuit
6V
For each bulb, R = 2Ω
1. Voltage through each
globe?
Parallel circuit
6V
For each bulb, R = 2Ω
1. Voltage through each
globe? 6V
Parallel circuit
6V
For each bulb, R = 2Ω
1. Total resistance?
Parallel circuit
6V
For each bulb, R = 2Ω
1. Total resistance?
1/R(total) = 1/R + 1/R
= 0.5 + 0.5 = 1
R(total) = 1/1
R (total) = 1 Ω
Which device is ohmic?
Which device is ohmic?
Rest of lesson…
 Revise through WACE book
OR
 Revise through STAWA book