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Compulsory 1: 1. Motion of particles: position and displacement of linear motion - formula: δx=x2-x1
Description of the speed of motion – velocity v=δx δt unit: meters per second (m s) ( t=t2-t1).
Description of how fast the velocity changes – acceleration Formula: a=δv δt unit: meter per square second (m s2).
2. Uniform variable speed linear motion.
Velocity formula: v=v0+at Displacement formula: s=v0t+1 2at 2=1 2(v0+v) t=1 2(v2-v0 2
Free fall motion (vo = 0).
In general calculations, g= or g=10m s 2 can be used
Formula: Mold jujube v end = gt h = 1 2gt 2 v 2 = 2gh
3. Force (unit: n).
Gravity g=mg Several elastic forces: pressure and support force Tensile force Hooke's law: f=kx (k—stiffness coefficient of spring).
Friction The magnitude of sliding friction is directly proportional to the pressure.
Formula: f= fn
The kinetic friction factor, whose value is related to the materials of two objects in contact with each other. fn: positive pressure.
Newton's second law f=ma
Compulsory 2. 1. Parabolic motion vx=v0 vy=gt tan =vy handicap code stupid vx=gt v0
Circular motion Linear velocity v=δl δt=2 r t unit: m s (t: period).
Angular velocity =δt=2 t unit: rad tanacus s (radians per second).
Centripetal acceleration a=v 2 r= 2 times r = (2 t) 2 times r = linear velocity times angular velocity unit m s 2
The centripetal force f=mv2r=m2 times r
2. Kepler's third law a 3 t 2=k
Gravitational force f=gmm r 2 (f=gm1m2 r 2).
Calculating the mass of a celestial body is given by gmm r 2=m 2 times r and =2 t to get m=4 2 times r 3 gt 2
The cosmic velocity mv 2 r = gmm r 2 gets v = root number gm r
3. Work w=fs
w=fscos unit joules (j) 1j=1n*1m=1n*m
Power p p=w t=fs t unit watt (w).
p=fv (can find the average power, can also find the instantaneous power 1. average power: when v is the average speed 2. instantaneous power: when v is the instantaneous speed at time t).
Gravitational potential energy ep=mgh per joule work done by gravity w=ep1-ep2
Kinetic energy ek=1 2mv2 unit joules Kinetic energy theorem w=1 2mv2 2-1 2mv1 2
That's all for the first year of high school.
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Look at the known quantities in the questions, there are generally related quantities (time, displacement, force, etc.) in the questions!! You have to find this amount, and that's the key to doing the problem!
That's what I want to know.
Just spend 5 bucks and buy a math formula book with an explanation.
Choose A, B, C
Because the stem does not say whether acceleration is the same as velocity or opposite. >>>More
Alas. s=(1/2)at^2
t=2,s=4 >>>More
I have hunger from Shanghai Middle School.