chap 10 Flashcards
stiffness formula
Hooke’s law 𝐹 = 𝑘 ΔL
when do you use cosine and sin on inclined forces weight
when force is not aligned you use cos when force in aligned it’s sin
how do you work out final v with Ep
v = square root((2 * Ep)/m)
with falling what suvat do you use
s = ut + 1/2at^2
if you want the a along the slope, what do you do
a = g * sin (theta of the ramp (not of the object to the ramp))
if Q ask’s for the Force down the slope e.g weight, what should you do
find what W*sin(theta of the ramp (not of the object to the ramp)) =
NOT what W =
(down the slope)
work done
Work=Force×Distance×cos(ϕ) unless you worked out F using cos
gravity
9.81
to calculate wasted energy
input - (EP + KE)
what should you not forget when dealing with power efficiency
w/t = P (don’t forget t)
what must you always consider
horizontal and vertical componenets of the force
for a slope with no friction what formula do you use to calculate the required energy
MGDsin theta = Ep
D = distance traveld by the object
what does the area mean on a force dicplacement graph
work done
efficiency equation
efficiency = (usefull energy output)/(total energy input)*100
When electrical energy is converted to heat for a heater what is the energy wasted
sound
for a load being pushed up how do you calculate it’s power output
gravitational potential/ time = Power input
If the question asks for efficiency as a ratio what do you do
give your answer as a fraction or decimal
If the question asks for efficiency as a percentage what do you do
multiply fraction by 100
what does flat terrain mean for energy storage
kinetic
energy transfers for a battery and Horizontal mass on a spring:
battery: chemical energy ➝ electrical energy ➝ light energy (if connected to a bulb)
Horizontal mass on a spring: elastic potential energy ➝ kinetic energy
elastic potential energy formula
all energy stores
