GO JESS!!! you can do it!!! =]
i'll be CHEERING for you xD
i've been studying for science, and OH MY GOSH ppl, take my warning, if you're planning to study for trials, better START NOW T_T
i'm like dying. i forgot half the topics we learnt last year
there's like 8 topics last year! ><"
1) origins of universe
2) electricity
3) plate tectonics
4) diseases
5) chemistry
6) earth and resources
7) reproduction
8) co-ordination
so START NOW!!!!!!
AND THERE'S MATH - don't mention it T_T
and there's friggin history and geo T_T
yay so anyways jess, if you happen to drop by before monday, i've very kindly summarised the notes on motion which i shall type up here =]
i omitted some of the more.. stupid definitions and stuff.. xD
position: object's distance + direction from fixed point
average speed = distance/time
average velocity = displacement/time + direction
a = (v-u)/t
In graphs
- gradient of line gives value of acceleration
- gradient of 0: car is travelling at constant velocity
- positive gradient: car is accelerating
- negative gradient: car is decelerating
- area under graph: distance travelled by car in each time period
A force is any action which causes an object to change its size, shape, state of motion (including acceleration, deceleration or change in direction) or rest
contact forces: friction, push/pull, air resistance, buoyancy, lift/thrust
field forces: gravity, magnetic, electrostatic
mass: measure of how heavy an object is (kg)
weight: amount of gravitational pull acting on an object (N)
Newton's 3 Laws of Gravitation
1. all objects in universe exert gravitational force on all other objects in universe
2. strength of gravitational force depends on mass of object
3. strength of gravitational force depends inversely on how far apart objects are (that is, the further apart the objects, the weaker the gravitational force)
Weight = mass x gravitational acceleration
on earth, gravitational accleration = 9.8
Static/sliding friction occurs when dry surfaces rub together; the force depends on:
1. type of surface
2. how hard surfaces are pressed together
Fluid friction occurs in liquid in gases, and is also known as "drag" or "air resistance"; force depends on:
1. viscosity of fluid
2. shape of object
3. speed of object
Friction changes kinetic energy to heat energy, and also wears away at surfaces causing damage. friction provides force to accelerate, stop, or change direction of the car.
Friction can be reduced by
1. rolling objects (vs sliding objects)
2. lubricants
3. polishing surfaces
4. blowing air between surfaces
Newton's 3 Laws of Motion
1. unless an unbalanced external force is applied to it
- an object at rest will remain at rest
- an object moving at constant speed in a straight line will continue to do so
Inertia is the reluctance of an object to change its state of rest or motion and it is dependant on the mass of the object
2. force = mass x acceleration
- acceleration is directly proportional to and in the same direction as the force acting on it (that is, as force increases, acceleration increases)
- acceleration is inversely proportional to mass (that is, as mass increases, acceleration decreases)
3. for every reaction, there is an equal and opposite reaction
hmm.. hopefully that was helpful =]
and YAY! i'm glad you like the skin jess =]
i'll be CHEERING for you xD
i've been studying for science, and OH MY GOSH ppl, take my warning, if you're planning to study for trials, better START NOW T_T
i'm like dying. i forgot half the topics we learnt last year
there's like 8 topics last year! ><"
1) origins of universe
2) electricity
3) plate tectonics
4) diseases
5) chemistry
6) earth and resources
7) reproduction
8) co-ordination
so START NOW!!!!!!
AND THERE'S MATH - don't mention it T_T
and there's friggin history and geo T_T
yay so anyways jess, if you happen to drop by before monday, i've very kindly summarised the notes on motion which i shall type up here =]
i omitted some of the more.. stupid definitions and stuff.. xD
position: object's distance + direction from fixed point
average speed = distance/time
average velocity = displacement/time + direction
a = (v-u)/t
In graphs
- gradient of line gives value of acceleration
- gradient of 0: car is travelling at constant velocity
- positive gradient: car is accelerating
- negative gradient: car is decelerating
- area under graph: distance travelled by car in each time period
A force is any action which causes an object to change its size, shape, state of motion (including acceleration, deceleration or change in direction) or rest
contact forces: friction, push/pull, air resistance, buoyancy, lift/thrust
field forces: gravity, magnetic, electrostatic
mass: measure of how heavy an object is (kg)
weight: amount of gravitational pull acting on an object (N)
Newton's 3 Laws of Gravitation
1. all objects in universe exert gravitational force on all other objects in universe
2. strength of gravitational force depends on mass of object
3. strength of gravitational force depends inversely on how far apart objects are (that is, the further apart the objects, the weaker the gravitational force)
Weight = mass x gravitational acceleration
on earth, gravitational accleration = 9.8
Static/sliding friction occurs when dry surfaces rub together; the force depends on:
1. type of surface
2. how hard surfaces are pressed together
Fluid friction occurs in liquid in gases, and is also known as "drag" or "air resistance"; force depends on:
1. viscosity of fluid
2. shape of object
3. speed of object
Friction changes kinetic energy to heat energy, and also wears away at surfaces causing damage. friction provides force to accelerate, stop, or change direction of the car.
Friction can be reduced by
1. rolling objects (vs sliding objects)
2. lubricants
3. polishing surfaces
4. blowing air between surfaces
Newton's 3 Laws of Motion
1. unless an unbalanced external force is applied to it
- an object at rest will remain at rest
- an object moving at constant speed in a straight line will continue to do so
Inertia is the reluctance of an object to change its state of rest or motion and it is dependant on the mass of the object
2. force = mass x acceleration
- acceleration is directly proportional to and in the same direction as the force acting on it (that is, as force increases, acceleration increases)
- acceleration is inversely proportional to mass (that is, as mass increases, acceleration decreases)
3. for every reaction, there is an equal and opposite reaction
hmm.. hopefully that was helpful =]
and YAY! i'm glad you like the skin jess =]