P1 - conservation and dissapation of energy

Question 1

name the main forms of energy

Answer 1

kinetic
light
sound
gravitational potential energy
thermal
elastic potential energy
chemical 
electrical
nuclear

Question 2

name the energy stores

Answer 2

chemical
thermal
kinetic
gravitational potential 
elastic potential

Question 3

name the transfer mechanisms

Answer 3

electrical
sound
light

Question 4

what is doing work?

Answer 4

transferring energy from one energy store to another

Question 5

what is the equation for work done?

Answer 5

work done (J) = force (n) x distance moved (m)

Question 6

what is the equation for gravitational potential energy?

Answer 6

gravitational potential energy (J) = weight (n) x change in height (m)

Question 7

what is the equation for weight?

Answer 7

weight (n) = mass (kg) x gravitational field strength ( 10n per kg)

Question 8

what is gravitational potential energy?

Answer 8

the energy stored in an object because of its position in the Earths gravitational field

Question 9

what is the equation for kinetic energy?

Answer 9

kinetic energy (J) = 1/2 x mass (kg) x velocity squared (m per s)

Question 10

what is the law of conservation of energy?

Answer 10

energy cannot be created or destroyed, just changed in form

Question 11

is this statement true?

gpe lost = kinetic energy gained

Answer 11

this is only true if air resistance and friction are ignored. in reality gpe would also be transferred into heat and sound energy

Question 12

What is the equation of elastic potential energy?

Answer 12

Elastic potential energy (J) = 1/2 x spring constant (N/m ) x extension squared

Question 13

What is wasted energy?

Answer 13

Wasted energy is the energy transfer that isn’t useful so it dissipates into the surroundings

as the energy dissipates the energy gets less and less useful

Question 14

What is useful energy?

Answer 14

Useful energy is the energy transferred to wear it js wanted and in the form it is wanted

Question 15

What is the equation of power?

Answer 15

power (W) = energy (J) divided by time (s)

Question 16

power is

Answer 16

the rate at which energy is transferred

Question 17

1 watt =

Answer 17

1 joule per second

Question 18

the more power rating the…

Answer 18

faster the rate at which energy transfers

Question 19

what is the equation of efficiency?

Answer 19

efficiency = useful power out / total power in x 100%

Question 20

rearranged formula of kinetic energy for mass

Answer 20

2KE/ v squared

Question 21

rearranged formula of kinetic energy for velocity

Answer 21

v = square root of ke / mass

Question 22

rearranged formula of elastic potential energy for spring constant

Answer 22

spring constant = 2elastic potential energy / extension squared

Question 23

rearranged formula of elastic potential energy for extension

Answer 23

square root of elastic potential energy/ spring constant x 1/2