Scalars and Vectors

Scalars:
A scalar quantity requires only size (magnitude)
to completely describe it.
Vectors:
A vector quantity requires size (magnitude) and a
direction to completely describe it.

Here are some vector and scalar quantities:
                         Scalar                               Vector
                          time                                   force
                          temperature                      weight
                          volume                          acceleration
                          distance                          displacement
                          speed                                velocity
                          energy                                momentum
                          mass                                  impulse
                          frequency
                         power
** Familiarise yourself with these scalar and vector quantities **

The knowledge and understanding content for this unit is given below.
Vectors
1. Distinguish between distance and displacement.
2. Distinguish between speed and velocity.
3. Define and classify vector and scalar quantities.
4. Use scale diagrams, or otherwise, to find the magnitude and direction of the resultant
of a number of displacements or velocities.
5. State what is meant by the resultant of a number of forces.
6. Carry out calculations to find the rectangular components of a vector.
7. Use scale diagrams, or otherwise, to find the magnitude and direction of the resultant
of a number of forces

Equations of motion
1. State that acceleration is the change in velocity per unit time.
2. Describe the principles of a method for measuring acceleration.
3. Draw an acceleration-time graph using information obtained from a velocity-time
graph for motion with a constant acceleration.
4. Use the terms “constant velocity” and “constant acceleration” to describe motion
represented in graphical or tabular form.
5. Show how the following relationships can be derived from basic definitions in
kinematics:
v = u + at
 s = ut +1/2 at2
 v2 = u2 + 2as

6. Carry out calculations using the above kinematic relationships.

Newton’s Second Law, energy and power
1. Define the newton.
2. Carry out calculations using the relationship F = ma in situations where resolution of
forces is not required.
3. Use free body diagrams to analyse the forces on an object.
4. Carry out calculations involving work done, potential energy, kinetic energy and
power

Gas laws
1. Describe how the kinetic model accounts for the pressure of a gas.
2. State that the pressure of a fixed mass of gas at constant temperature is inversely
proportional to its volume.
3. State that the pressure of a fixed mass of gas at constant volume is directly
proportional to its temperature measured in kelvin K.
4. State that the volume of a fixed mass of gas at constant pressure is directly
proportional to its temperature measured in kelvin K.
5. Carry out calculations to convert temperatures in oC to K and vice versa.
6. Carry out calculations involving pressure, volume and temperature of a fixed mass of
gas using the general gas equation.
7. Explain what is meant by absolute zero of temperature.
8. Explain the pressure-volume, pressure-temperature and volume-temperature laws
qualitatively in terms of the kinetic model


Momentum and impulse
1. State that momentum is the product of mass and velocity.
2. State that the law of conservation of linear momentum can be applied to the
interaction of two objects moving in one dimension, in the absence of net external
forces.
3. State that an elastic collision is one in which both momentum and kinetic energy are
conserved.
4. State that an inelastic collision is one in which only momentum is conserved.
5. Carry out calculations concerned with collisions in which the objects move in only
one dimension.
6. Carry out calculations concerned with explosions in one dimension.
7. Apply the law of conservation of momentum to the interaction of two objects moving
in one direction to show that:
a) the changes in momentum of each object are equal in size and opposite in direction
b) the forces acting on each object are equal in size and opposite indirection.
8. State that impulse = force × time.
9. State that impulse = change in momentum.
10. Carry out calculations using the relationship, impulse = change of momentum.

Density and Pressure
1. State that density is mass per unit volume.
2. Carry out calculations involving density, mass and volume.
3. Describe the principles of a method for measuring the density of air.
4. State and explain the relative magnitudes of the densities of solids, liquids and gases.
5. State that pressure is the force per unit area, when the force acts normal to the surface.
6. State that one pascal is one newton per square metre.
7. Carry out calculations involving pressure, force and area.
8. State that the pressure at a point in a fluid at rest is given by h8g.
9. Carry out calculations involving pressure, density and depth.
10. Explain buoyancy force (upthrust) in terms of the pressure difference between the top
and bottom of an object.

Gas laws
1. Describe how the kinetic model accounts for the pressure of a gas.
2. State that the pressure of a fixed mass of gas at constant temperature is inversely
proportional to its volume.
3. State that the pressure of a fixed mass of gas at constant volume is directly
proportional to its temperature measured in kelvin K.
4. State that the volume of a fixed mass of gas at constant pressure is directly
proportional to its temperature measured in kelvin K.
5. Carry out calculations to convert temperatures in oC to K and vice versa.
6. Carry out calculations involving pressure, volume and temperature of a fixed mass of
gas using the general gas equation.
7. Explain what is meant by absolute zero of temperature.
8. Explain the pressure-volume, pressure-temperature and volume-temperature laws
qualitatively in terms of the kinetic model.