SP3z - Conservation Of Energy

Question 1

What is the principal of conservation of energy?

Answer 1

Energy cannot be created or destroyed, only stored or transferred

Question 2

Analyse the changes involved in the way energy is stored when an object is projected upwards or up a slope

Answer 2

• store of kinetic energy throughout

- work done against gravity transferred to GPE

Question 3

Analyse the changes involved in the way energy is stored when a moving object hits an obstacle

Answer 3

• store of kinetic energy to begin with
• then work done against friction to convert this store into sound, heating and elastic potential energy
• sound and heating dissipate to the surroundings to be stored as thermal energy

Question 4

Analyse the changes involved in the way energy is stored when an object is being accelerated by a constant force

Answer 4

• work done against friction adding to the store of kinetic energy

Question 5

Analyse the changes involved in the way energy is stored when a vehicle is slowing down

Answer 5

• work done against friction to move energy from the KE store to dissipate it to the surroundings by heating so it ends up as thermal energy stored in the surroundings

Question 6

Analyse the changes involved in the way energy is stored when bringing water to a boil in an electric kettle

Answer 6

• electrical energy transferred to the kettle
• work done against electrical resistance causes heating in the element
• heating dissipates into the water where thermal energy is stored

Question 7

As you go through an energy transfer, _______________ energy is wasted

Answer 7

More and more

Question 8

What is the only machine that can be 100% efficient and why?

Answer 8

A heater is designed to transfer energy by heat. As all machines do this anyway, the heater is the only one that doesn’t do it as waste

Question 9

How does making the walls thicker affect how quickly a warm building will cool down, and why?

Answer 9

Making walls thicker will slow the cooling, because thicker walls are better insulators than thinner walls

Question 10

What does thermal conductivity mean?

Answer 10

How well a material can transfer heat

Question 11

How does making the walls out of a material with a higher thermal conductivity affect how quickly a warm building will cool down, and why?

Answer 11

Higher thermal conductivity means better heat transfer, so higher thermal conductivity means the building will cool down faster

Question 12

DO QUESTIONS 11 AND 12!!!

Answer 12

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