WORK, ENERGY, POWER

work formulas

w = F△x

full formula is F(II)cos△x

w = Fcos0△x

value of work when force is perpendicular to displacement

0

when it is 90 degrees

this also happens when the force acts vertically while displacement is horizontal

work energy theorem

when net external force does work (on an object), the CHANGE in kinetic energy (FINAL - INITIAL) is EQUAL to WORK done

work = change in ke

work energy theorem formula

W = 1/2mv²(f) -1/2mv²(i)

W can be expressed/substi too, as Fcos0△x or F△x

work done by gravity formula

W = Fcos△y, OR:

W = mg(y0-yf)

GPE definition

energy an object has due to its position, relative to surface of earth

conservation of mechanical energy formula

mgh(F) + 1/2mv²(F) = mgh(i) + 1/2mv²(i)

power formula

work/time

OR

change in energy/time

units of power

WATT (defined as one joule per second 1J/S)
or horsepower

how many watts is 1 horsepower

745.7

how many foot-pounds-per-second is 1 horsepower

550

internal force

forces that objects WITHIN SYSTEM exert on eachother

external force

forces exerted on object OUTSIDE SYSTEM

when is total linear momentum constant?

when the systems are isolated

what is the sum of average external forces in ISOLATED SYSTEMS

0

impulse formula

product of average force and time

J = F△t

momentum formula

p = mv

momentum is a vector

impulse-momentum theorem

when net force acts on an object, impulse and momentum are equal to echother

impulse-momentum formula

F△t = mv(f) - mv(i)

elastic collision

KE conserved, objects remain separated, total KE after collision = total KE before collision

‘perfectly/completely’ inelastic collision

KE not conserved. objects stick together

elastic collision formula for MOMENTUM AND KINETIC ENERGY

m1v1 + m2v2 (i) = m1v1 + m2v2 (F) = MOMENTUM
equation with the ½ = KINETIC ENERGY