Physics- Forces,motion,energy

speed formula

distance/time

acceleration

change in velocity/time

stopping distance

thinking distance + braking distance

Force (N)

applied to an object to potentially change shape, motion or state

resultant forces

sum of all forces acting on an object

types of acting forces

1. tensile

2. torsional

3. weight

4. normal

5. friction

6. resistive

7. electrostatic

8. magnetic

9. thrust

10. upthrust

contact forces

• drag

• uptrust

• friction

non-contact

• weight

• electrostatic

• magnetic

force

mass x acceleration

weight

mass x gravitational field strength

newtons 1st law

body will remain in its state of motion, unless acted by a non-zero external resultant force

newtons 2nd law

body will experience acceleration in same direction as non-zero external resultant force

newtons 3rd law

for every force applied there is always an equal and opposite force acting

elastic deformation

object retains original shape and length after applied force is removed

plastic deformation

object does not retain original shape and length after applied force is removed

hookes law

force= spring constant x extension

principle of energy

energy cannot be created or destroyed only stored and transferred 

energy stores (8)

1. nuclear

2. gravitational potential 

3. thermal 

4. magnetic

5. elastic potential

6. kinetic

7. electrostatic

8. chemical

energy transfers (4)

• mechanical

• heating

• radiation

• electrical 

efficiency

useful output/total input x 100

kinetic energy

\frac12mv^2

GPE

mass x grav field strength x height

pressure

acceleration x force

work done

force x distance

conduction

flow of thermal energy through solid from high to low temp

Why are metals good conductors?

because of delocalised electrons

poor conductors

• wood

• glass

• plastic

convection

flow of thermal energy through fluid from high to low temp

density

mass/volume

radiation

emission of infrared waves

what makes a good IR absorber/emitter

• less shiny

• darker

• rough surface

insulators

anything that minimises or prevents heat transfer