definitionsAS物理定义大全
合集下载
- 1、下载文档前请自行甄别文档内容的完整性，平台不提供额外的编辑、内容补充、找答案等附加服务。
- 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
- 3、如文档侵犯您的权益，请联系客服反馈,我们会尽快为您处理(人工客服工作时间：9:00-18:30)。
Instantaneous Acceleration
De finition In S.I. a quantity is represented by a number a unit, (e.g. m = 3.0 kg).
A scalar is a quantity that has magnitude only. A vector is a quantity that has magnitude and direction.
Unit: V.
Page 3
Section
Ite m
2.1 (a) Progressive wave
2.1 (b) Transverse wave Longitudinal wave
2.1 (d) Polarised wave
Wavelength of a progressive wave(λ ) Frequency of a wave (ƒ) Period T speed of a wave
% Efficiency
=
100
useful work
work (or energy) out (or energy) put in
UUnNiItT: nSon: eNONE
This is the rate of flow of electric charge. I = ∆Q/∆t. Unit: A
Kinetic energy 1.3( h) Power
Efficiency of a system
1.4 (h) Electric current, I.
De finition The terminal velocity is the constant, maximum velocity of an object when the resistive forces on it are equal and opposite to the ‘accelerating’ force (e.g. pull of gravity). Work done by a force is the product of the magnitude of the force and the distance moved in the direction of the force.( W.D. = Fxcos )
Section
Ite m
1.2 (e) Terminal Velocity
1.3 (a) Work
1.3 (b) Hooke’s Law
Spring constant, k
1.3 (d) 1.3 (e)
Energy
Principle of conservation of energy Potential energy
as the force the perpendicular distance from the point to the line of action of the force,
i.e. moment = F d. Unit: Nm. [N.B. the unit is not J] For a system to be in equilibrium, sum of anticlockwise moments about a point = sum of clockwise moments about the same point. The centre of gravity is the single point within a body at which the entire weight of the body may be considered to act
The ability to do work. Unit: J
Energy cannot be created or destroyed, only transferred from
one form to another. Energy is a scalar.
This is energy possessed by virtue of position. (e.g. Gravitational PE
total time taken
t
Unit: ms-1.
instantaneous speed = rate of change of distance
Unit: ms-1.
total displacement Mean velocity =
total time taken Unit: ms-1. The velocity of a body is the rate of change of displacement. Unit: ms-1
The mass of a body its acceleration is equal to the vector sum of the forces acting on the body. This vector sum is called the resultant force.
This means finding vectors (the so-called components) in these directions, which add together vectorially to make the original vector, and so, together, are equivalent to this
Page 1 Section 1.1 (a) 1.1 (c) 1.1 (d)
1.1 (f) 1.1 (h)
1.1 (i)
1.1 (j)
1.1 (k) 1.1 (l) 1.2 (a)
Ite m Quantity Scalar Vector Force
Newton’s Third Law F=ma
Resolving a vector into components in particular directions Density of a material
1.5 (a) 1.5 (c) 1.5 (d) 1.5 (g)
1.5 (k)
1.6 (a) 1.6 (f)
Potential difference (p.d.), V.
Ohm’s Law.
Electrical Resistance, R.
Resistivity,
Superconducting transition temperature
The current flowing through a metal wire at constant temperature is proportional to the p.d. across it. The resistance of a conductor is the ratio of p.d. (V) across it to the current (I) in it. R = V / I Unit: ohm () [= VA-1]. The resistance, R, of a metal wire of length L and cross-sectional area A is given by R = L / A, in which the resistivity, is a constant (at constant temperature) for the material of the wire.
Mean Acceleration = change in velocity v
time taken
t
Unit: ms-2.来自The instantaneous acceleration of a body is its rate of change
of velocity. Unit: ms-2
Page 2
A force on a body is a push or a pull acting on the body from some external body.
Unit: N If a body A exerts a force on a body B, then B exerts an equal and opposite force on A.
Unit: m
The temperature at which a material, when cooled, loses all its electrical resistance, and becomes super-conducting. Some materials (e.g. copper) never become superconducting however low the temperature.
= mgh). Unit: J
Energy due to motion. Unit: J
The work done per unit time taken. This is the work done per
second, or energy transferred per second.
Unit: watt (W) [= Js-1].
Electric charge cannot be created or destroyed, (though positive and negative charges can neutralise each other). Charge cannot pile up anywhere. The e.m.f. of a source is the energy converted from some other form (e.g. chemical) to electrical potential energy per coulomb of charge flowing through the source.
The Law of Conservation of Charge. e.m.f.
The p.d. between two points is the energy converted from electrical potential energy to some other form per coulomb of charge flowing from one point to the other. Unit: volt (V) [= JC-1].
Unit: J [= Nm] Provided the elastic limit is not exeeded, the extension is directly proportional to the load applied on the object.
The spring constant is the force per unit extension. Unit: Nm-1.
The change in position. The displacement of a point B
from a point A is the shortest distance from A to B,
together with the direction. Unit: m.
Mean speed = total distance travelled x
vector.
density mass volume
Unit: kg m3
in which mass and volume apply to any sample of the
material.
The moment (or torque) of a force about a point is defined
Moment (or torque) of a force.
The principle of moments. Centre of gravity. Displacement
Mean Speed
Instantaneous Speed Mean Velocity
Instantaneous Velocity Mean Acceleration
De finition In S.I. a quantity is represented by a number a unit, (e.g. m = 3.0 kg).
A scalar is a quantity that has magnitude only. A vector is a quantity that has magnitude and direction.
Unit: V.
Page 3
Section
Ite m
2.1 (a) Progressive wave
2.1 (b) Transverse wave Longitudinal wave
2.1 (d) Polarised wave
Wavelength of a progressive wave(λ ) Frequency of a wave (ƒ) Period T speed of a wave
% Efficiency
=
100
useful work
work (or energy) out (or energy) put in
UUnNiItT: nSon: eNONE
This is the rate of flow of electric charge. I = ∆Q/∆t. Unit: A
Kinetic energy 1.3( h) Power
Efficiency of a system
1.4 (h) Electric current, I.
De finition The terminal velocity is the constant, maximum velocity of an object when the resistive forces on it are equal and opposite to the ‘accelerating’ force (e.g. pull of gravity). Work done by a force is the product of the magnitude of the force and the distance moved in the direction of the force.( W.D. = Fxcos )
Section
Ite m
1.2 (e) Terminal Velocity
1.3 (a) Work
1.3 (b) Hooke’s Law
Spring constant, k
1.3 (d) 1.3 (e)
Energy
Principle of conservation of energy Potential energy
as the force the perpendicular distance from the point to the line of action of the force,
i.e. moment = F d. Unit: Nm. [N.B. the unit is not J] For a system to be in equilibrium, sum of anticlockwise moments about a point = sum of clockwise moments about the same point. The centre of gravity is the single point within a body at which the entire weight of the body may be considered to act
The ability to do work. Unit: J
Energy cannot be created or destroyed, only transferred from
one form to another. Energy is a scalar.
This is energy possessed by virtue of position. (e.g. Gravitational PE
total time taken
t
Unit: ms-1.
instantaneous speed = rate of change of distance
Unit: ms-1.
total displacement Mean velocity =
total time taken Unit: ms-1. The velocity of a body is the rate of change of displacement. Unit: ms-1
The mass of a body its acceleration is equal to the vector sum of the forces acting on the body. This vector sum is called the resultant force.
This means finding vectors (the so-called components) in these directions, which add together vectorially to make the original vector, and so, together, are equivalent to this
Page 1 Section 1.1 (a) 1.1 (c) 1.1 (d)
1.1 (f) 1.1 (h)
1.1 (i)
1.1 (j)
1.1 (k) 1.1 (l) 1.2 (a)
Ite m Quantity Scalar Vector Force
Newton’s Third Law F=ma
Resolving a vector into components in particular directions Density of a material
1.5 (a) 1.5 (c) 1.5 (d) 1.5 (g)
1.5 (k)
1.6 (a) 1.6 (f)
Potential difference (p.d.), V.
Ohm’s Law.
Electrical Resistance, R.
Resistivity,
Superconducting transition temperature
The current flowing through a metal wire at constant temperature is proportional to the p.d. across it. The resistance of a conductor is the ratio of p.d. (V) across it to the current (I) in it. R = V / I Unit: ohm () [= VA-1]. The resistance, R, of a metal wire of length L and cross-sectional area A is given by R = L / A, in which the resistivity, is a constant (at constant temperature) for the material of the wire.
Mean Acceleration = change in velocity v
time taken
t
Unit: ms-2.来自The instantaneous acceleration of a body is its rate of change
of velocity. Unit: ms-2
Page 2
A force on a body is a push or a pull acting on the body from some external body.
Unit: N If a body A exerts a force on a body B, then B exerts an equal and opposite force on A.
Unit: m
The temperature at which a material, when cooled, loses all its electrical resistance, and becomes super-conducting. Some materials (e.g. copper) never become superconducting however low the temperature.
= mgh). Unit: J
Energy due to motion. Unit: J
The work done per unit time taken. This is the work done per
second, or energy transferred per second.
Unit: watt (W) [= Js-1].
Electric charge cannot be created or destroyed, (though positive and negative charges can neutralise each other). Charge cannot pile up anywhere. The e.m.f. of a source is the energy converted from some other form (e.g. chemical) to electrical potential energy per coulomb of charge flowing through the source.
The Law of Conservation of Charge. e.m.f.
The p.d. between two points is the energy converted from electrical potential energy to some other form per coulomb of charge flowing from one point to the other. Unit: volt (V) [= JC-1].
Unit: J [= Nm] Provided the elastic limit is not exeeded, the extension is directly proportional to the load applied on the object.
The spring constant is the force per unit extension. Unit: Nm-1.
The change in position. The displacement of a point B
from a point A is the shortest distance from A to B,
together with the direction. Unit: m.
Mean speed = total distance travelled x
vector.
density mass volume
Unit: kg m3
in which mass and volume apply to any sample of the
material.
The moment (or torque) of a force about a point is defined
Moment (or torque) of a force.
The principle of moments. Centre of gravity. Displacement
Mean Speed
Instantaneous Speed Mean Velocity
Instantaneous Velocity Mean Acceleration