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Hello Everyone! Here's the much requested thread for Physics. It contains pointers for the paper and some clarifications of syllabus content. 
- Vector quantities have both a direction and magnitude; scalars only have magnitude.
- Measurements that are long and need a flexible (curved) measuring tool are measured using measuring tape.
- Micrometer has an accuracy of 0.001 cm (i.e. 0.01 mm).
- Vernier calipers can be used to measure the INTERNAL diameter of a substance DIRECTLY. They have an accuracy of 0.01 cm (0.1 mm).
- Speed is the DISTANCE traveled per unit time.
- Velocity is the DISPLACEMENT per unit time.
- Average Speed = Total Distance/Time.
- Acceleration is the change in velocity per unit time. It may be a change in direction AND/OR a change in speed.
- Uniform accelerating means that the change in velocity per unit time is CONSTANT.
- Non-uniform acceleration is change in velocity that varies per unit time.
- The gradient of a distance-time graph gives the speed of a body.
- The gradient of a speed-time graph gives the acceleration of a body. The area under the graph gives the distance.
- Uniform acceleration is a Straight Line (with constant gradient) in a speed-time graph. Non-uniform acceleration is a Curve.
- Acceleration (whether uniform or non-uniform) is shown as a curve on a distance-time graph.
- Constant speed on speed-time graph is a straight line parallel to x-axis. It is a straight line with constant gradient in a distance-time graph.
- Acceleration of Free fall ON EARTH = 10 m/s^2.
- If air resistance is there, a lighter body reaches terminal velocity quickly and hence falls less slowly then a heavier body (which accelerates more).
- With negligible air resistance, all bodies fall at the same time since the Acceleration of Free Fall is a constant.
- Newton's Third Law -> Every action has an equal and opposite reaction.
- If a body has balanced forces, it is moving with constant speed OR is stationary.
- If a body has unbalanced forces, it is swinging or accelerating.
- A force may bring about a change in motion by; increasing the speed of the body, changing the stationary state of a body, stopping a moving body.
- If the road is dry and rough (normal conditions) then the frictional force is great and cars STOP quickly. If the road is wet (or oily) and smooth then the frictional force is less and cars STOP less quickly.
- Circular motion is caused by a force acting TOWARDS THE CENTER of the circle, this centripetal force is NECESSARY for circular motion.
- Electrons have circular motion because of electrostatic forces. Planets and Moons have circular motion because of the gravity acting towards the center of the attracting body (Earth for the Moon and Sun for the planets).
- Inertia is the resistance of a body to START moving or STOP moving. It is because of the mass of a body.
- Mass is measured using Beam Balance and Electronic Balance. Weight is measured using a Spring Balance.
- Moment is the turning effect of a force. It is used in Door Knobs, Wrenches, See Saws, etc.
- The principle of moments states that if a body is in a stationary position then the clockwise moments about a point are equal to the anticlockwise moments about the same point.
- The principle of moments can be verified by setting up a rule with a pivot at the center and calculating moments about the pivot when the rule is stationary.
- A MORE stable object is one which has its center of mass as low as possible and has a broad area.
- A force can bring about a change in the size and shape of a body (compression and stretching).
- The height of the mercury/water column = atmospheric pressure.
- Pressure increases with increasing depth (in liquids).
- Universal gas law is (P1 * V1)/T1 = (P2 * V2)/T2.
- Kinetic energy is possessed by bodies in motion. Gravitational potential energy is possessed by the elevated position of bodies. Chemical energy is stored energy found inside us, foods, batteries, etc.
- Principle of conversation of energy states that energy is neither created nor destroyed, it is converted from one form to another.
- Power generation creates great pollution problems, waste gases, contribution to global warming, harmful toxic substances.
- Conduction occurs because of the the movement of molecules (that pass on energy).
- Convection occurs because of the change in density of a liquid/gas.
- Radiation occurs because of the emission of infra-red rays from all heat emitting bodies.
- Shiny surfaces are bad emitters and absorbents of radiation. Black surfaces are good absorbents and emitters.
- Heat travels to and from homes by walls, windows, roofs, doors.
- Heat loss can be prevented by; double glazed windows, insulation of lofts using glass, non-conducting material for doors, shiny paint.
- Themocouple is the best thermometer, it has a wide range and it responds rapidly.
- For normal liquid in glass thermometers:
(i) Responsiveness is how quickly the thermometer responds to a temperature range.
(ii) The sensitivity is how big a change is there (for example in volume of mercury) for a change in temperature.
(iii) A thin bulb conducts the heat from surroundings quickly so it is used to increase responsiveness.
(iv) The volume of liquid should be less so that the liquid expands and reacts to the temperature change quickly.
(v) For sensitivity, a narrow bore (inner line) of thermometer is used so that the expanded liquid travels further for a little change in temperature.
(vi) A liquid that expands quite a lot for a temperature change is used to increase sensitivity.
(vii) Increased sensitivity = Less range and the converse is also true.
(viii) Linearity is the equal expansion of a liquid on heating.
- Heat capacity is the heat required to raise the temperature of a body by One deg. Centigrade/ One Kelvin.
- Specific heat capacity is the heat required to raise the temperature of 1 kg of a body by One deg. Centigrade/ One Kelvin.
- Latent heat is the heat required to change a body from solid to liquid or liquid to gas (and their reverse).
- Specific latent heat is the heat required to change 1 kg of a body from solid to liquid or liquid to gas (and their reverse).
- Solids expand the least, Liquids expand more than solid but less than liquids, Gases expand the most.
- Railway tracks, Bimetallic strip in thermostats and Gaps in bridges are all because of thermal expansion (and contraction).
- In a bimetallic strip, the metal that expands more is on top of the curve (and on the bottom of the curve when it is contracted).
- Evaporation causes cooling because the energetic molecules leave the surface.
- Rate of evaporation increases as temperature, surface area, wind, draught increases.
- Longitudinal waves are parallel to the motion of vibration. Transverse waves are perpendicular to the motion of vibration.
- Wave front -> A surface over which all the points that are vibrating in the same phase lie.
- Refraction of waves is due to a change in speed (the frequency is always constant).
- Short sight, rays converge before cornea, fixed using diverging lens.
- Long sight, rays do not converge on the cornea (converge after), fixed using converging lens.
Continued Below.
- Vector quantities have both a direction and magnitude; scalars only have magnitude.
- Measurements that are long and need a flexible (curved) measuring tool are measured using measuring tape.
- Micrometer has an accuracy of 0.001 cm (i.e. 0.01 mm).
- Vernier calipers can be used to measure the INTERNAL diameter of a substance DIRECTLY. They have an accuracy of 0.01 cm (0.1 mm).
- Speed is the DISTANCE traveled per unit time.
- Velocity is the DISPLACEMENT per unit time.
- Average Speed = Total Distance/Time.
- Acceleration is the change in velocity per unit time. It may be a change in direction AND/OR a change in speed.
- Uniform accelerating means that the change in velocity per unit time is CONSTANT.
- Non-uniform acceleration is change in velocity that varies per unit time.
- The gradient of a distance-time graph gives the speed of a body.
- The gradient of a speed-time graph gives the acceleration of a body. The area under the graph gives the distance.
- Uniform acceleration is a Straight Line (with constant gradient) in a speed-time graph. Non-uniform acceleration is a Curve.
- Acceleration (whether uniform or non-uniform) is shown as a curve on a distance-time graph.
- Constant speed on speed-time graph is a straight line parallel to x-axis. It is a straight line with constant gradient in a distance-time graph.
- Acceleration of Free fall ON EARTH = 10 m/s^2.
- If air resistance is there, a lighter body reaches terminal velocity quickly and hence falls less slowly then a heavier body (which accelerates more).
- With negligible air resistance, all bodies fall at the same time since the Acceleration of Free Fall is a constant.
- Newton's Third Law -> Every action has an equal and opposite reaction.
- If a body has balanced forces, it is moving with constant speed OR is stationary.
- If a body has unbalanced forces, it is swinging or accelerating.
- A force may bring about a change in motion by; increasing the speed of the body, changing the stationary state of a body, stopping a moving body.
- If the road is dry and rough (normal conditions) then the frictional force is great and cars STOP quickly. If the road is wet (or oily) and smooth then the frictional force is less and cars STOP less quickly.
- Circular motion is caused by a force acting TOWARDS THE CENTER of the circle, this centripetal force is NECESSARY for circular motion.
- Electrons have circular motion because of electrostatic forces. Planets and Moons have circular motion because of the gravity acting towards the center of the attracting body (Earth for the Moon and Sun for the planets).
- Inertia is the resistance of a body to START moving or STOP moving. It is because of the mass of a body.
- Mass is measured using Beam Balance and Electronic Balance. Weight is measured using a Spring Balance.
- Moment is the turning effect of a force. It is used in Door Knobs, Wrenches, See Saws, etc.
- The principle of moments states that if a body is in a stationary position then the clockwise moments about a point are equal to the anticlockwise moments about the same point.
- The principle of moments can be verified by setting up a rule with a pivot at the center and calculating moments about the pivot when the rule is stationary.
- A MORE stable object is one which has its center of mass as low as possible and has a broad area.
- A force can bring about a change in the size and shape of a body (compression and stretching).
- The height of the mercury/water column = atmospheric pressure.
- Pressure increases with increasing depth (in liquids).
- Universal gas law is (P1 * V1)/T1 = (P2 * V2)/T2.
- Kinetic energy is possessed by bodies in motion. Gravitational potential energy is possessed by the elevated position of bodies. Chemical energy is stored energy found inside us, foods, batteries, etc.
- Principle of conversation of energy states that energy is neither created nor destroyed, it is converted from one form to another.
- Power generation creates great pollution problems, waste gases, contribution to global warming, harmful toxic substances.
- Conduction occurs because of the the movement of molecules (that pass on energy).
- Convection occurs because of the change in density of a liquid/gas.
- Radiation occurs because of the emission of infra-red rays from all heat emitting bodies.
- Shiny surfaces are bad emitters and absorbents of radiation. Black surfaces are good absorbents and emitters.
- Heat travels to and from homes by walls, windows, roofs, doors.
- Heat loss can be prevented by; double glazed windows, insulation of lofts using glass, non-conducting material for doors, shiny paint.
- Themocouple is the best thermometer, it has a wide range and it responds rapidly.
- For normal liquid in glass thermometers:
(i) Responsiveness is how quickly the thermometer responds to a temperature range.
(ii) The sensitivity is how big a change is there (for example in volume of mercury) for a change in temperature.
(iii) A thin bulb conducts the heat from surroundings quickly so it is used to increase responsiveness.
(iv) The volume of liquid should be less so that the liquid expands and reacts to the temperature change quickly.
(v) For sensitivity, a narrow bore (inner line) of thermometer is used so that the expanded liquid travels further for a little change in temperature.
(vi) A liquid that expands quite a lot for a temperature change is used to increase sensitivity.
(vii) Increased sensitivity = Less range and the converse is also true.
(viii) Linearity is the equal expansion of a liquid on heating.
- Heat capacity is the heat required to raise the temperature of a body by One deg. Centigrade/ One Kelvin.
- Specific heat capacity is the heat required to raise the temperature of 1 kg of a body by One deg. Centigrade/ One Kelvin.
- Latent heat is the heat required to change a body from solid to liquid or liquid to gas (and their reverse).
- Specific latent heat is the heat required to change 1 kg of a body from solid to liquid or liquid to gas (and their reverse).
- Solids expand the least, Liquids expand more than solid but less than liquids, Gases expand the most.
- Railway tracks, Bimetallic strip in thermostats and Gaps in bridges are all because of thermal expansion (and contraction).
- In a bimetallic strip, the metal that expands more is on top of the curve (and on the bottom of the curve when it is contracted).
- Evaporation causes cooling because the energetic molecules leave the surface.
- Rate of evaporation increases as temperature, surface area, wind, draught increases.
- Longitudinal waves are parallel to the motion of vibration. Transverse waves are perpendicular to the motion of vibration.
- Wave front -> A surface over which all the points that are vibrating in the same phase lie.
- Refraction of waves is due to a change in speed (the frequency is always constant).
- Short sight, rays converge before cornea, fixed using diverging lens.
- Long sight, rays do not converge on the cornea (converge after), fixed using converging lens.
Continued Below.
