IB Physics Topic 2 Key Concepts

Vectors have:

magnitude and direction

Velocity and Speed

Are not equal

Units of acceleration

meters per second squared

displacement

the distance moved in a particular direction (s)

velocity

the rate of change of displacement (v)

speed

the rate of change of distance (s)

acceleration

the rate of change of velocity (a)

In the constant acceleration equations, "u" is

u is initial velocity

In the constant acceleration equations, "v" is

v is final velocity

In the constant acceleration equations, "a" is

a is acceleration

In the constant acceleration equations, "t" is

t is time

In the constant acceleration equations, "s" is

s is distance

Hookes Law

F = kx

What is the first step to solving a Force problem?

Draw a force diagram

When working out a problem about the acceleration of a block down a slope, how does one find the component of force that causes the block to move down the slope?

Fdownslope = mgsinθ = wsinθ, where w is weight

When working out a problem about forces on a block on a slope, what is the angle?

The angle used in the equation is the same as the angle of the slope against the horizontal

Newton's First Law

a resultant force causes acceleration, no resultant force causes no resultant acceleration

Newtons Second Law

F = ma

Equilibrium

∑F = zero

Newton's Third Law

for every action on one object there is an equal but opposite reaction on the other object

Conservation of Momentum

linear momentum is conserved if there is no resultant external force

Work is only done

in the direction of the force

amount of energy transfered =

amount of work done

Energy is in the unit of

Joules

Work is in the unit of

Joules

Equation of Kinetic energy

KE = ½mv²

Equation of Gravitational Potential Energy

GPE = mgh

Equation of elastic potential energy

EPE = ½kx²

Law of Conservation of Energy

Energy is always conserved, never lost, energy only changes forms, the total energy in the universe never changes

Power

energy transferred over time

Equations for Power

P = W/t, where W is work and t is time

Efficiency is the ratio of

useful energy out over total energy in

Efficiency is expressed graphically using

Sanskey Diagrams

In Uniform Circular Motion

Speed is constant, velocity is constantly changing, and the object is constantly accelerating

Centripetal acceleration

(ac) = v²/r

Centripetal Force

(Fc) = mv²/r = m(ac)/r

Centripetal Force

Does not do work