chap 10

Question 1

stiffness formula

Answer 1

Hooke’s law 𝐹 = 𝑘 ΔL

Question 2

Answer 2

Question 3

when do you use cosine and sin on inclined forces weight

Answer 3

when force is not aligned you use cos when force in aligned it’s sin

Question 4

how do you work out final v with Ep

Answer 4

v = square root((2 * Ep)/m)

Question 5

with falling what suvat do you use

Answer 5

s = ut + 1/2at^2

Question 6

if you want the a along the slope, what do you do

Answer 6

a = g * sin (theta of the ramp (not of the object to the ramp))

Question 7

if Q ask’s for the Force down the slope e.g weight, what should you do

Answer 7

find what W*sin(theta of the ramp (not of the object to the ramp)) =
NOT what W =
(down the slope)

Question 8

work done

Answer 8

Work=Force×Distance×cos(ϕ) unless you worked out F using cos

Question 9

gravity

Answer 9

9.81

Question 10

to calculate wasted energy

Answer 10

input - (EP + KE)

Question 11

what should you not forget when dealing with power efficiency

Answer 11

w/t = P (don’t forget t)

Question 12

what must you always consider

Answer 12

horizontal and vertical componenets of the force

Question 13

for a slope with no friction what formula do you use to calculate the required energy

Answer 13

MGDsin theta = Ep

D = distance traveld by the object

Question 14

what does the area mean on a force dicplacement graph

Answer 14

work done

Question 15

efficiency equation

Answer 15

efficiency = (usefull energy output)/(total energy input)*100

Question 16

When electrical energy is converted to heat for a heater what is the energy wasted

Answer 16

sound

Question 17

for a load being pushed up how do you calculate it’s power output

Answer 17

gravitational potential/ time = Power input

Question 18

If the question asks for efficiency as a ratio what do you do

Answer 18

give your answer as a fraction or decimal

Question 19

If the question asks for efficiency as a percentage what do you do

Answer 19

multiply fraction by 100

Question 20

what does flat terrain mean for energy storage

Answer 20

kinetic

Question 21

energy transfers for a battery and Horizontal mass on a spring:

Answer 21

battery: chemical energy ➝ electrical energy ➝ light energy (if connected to a bulb)
Horizontal mass on a spring: elastic potential energy ➝ kinetic energy

Question 22

elastic potential energy formula

Answer 22

Question 23

Answer 23

Question 24

all energy stores

Answer 24

Question 25

If a question asks about the ‘loss of kinetic energy’ what should you remember

Answer 25

remember not to include a negative sign since energy is a scalar quantity.