P1.2 Conservation Of Energy

Question 1

What is a closed system?

Answer 1

A system where no energy transfers take place out of or into the energy stores of the system

Question 2

What is a system?

Answer 2

An object or a group of objects

Question 3

What is the principle of the conservation of energy?

Answer 3

Energy cannot be created or destroyed

Question 4

Why does a bungee jumper not return to the original height of the jump?

Answer 4

Because some energy was transferred to the energy store of the surroundings by heating as the rope stretched and shortened again

Question 5

Describe the changes in energy stores during a plane journey

Answer 5

• At the start, the fuel tank is full. The fuel is a chemical energy store.
• When the plane is not moving it has zero kinetic energy store
• As it starts to move, the chemical store is converted to a kinetic store
• At lift off, the gravitational potential store starts to increase and the chemical store of the fuel will decrease
• Eventually, all of the chemical energy in the fuel is transferred to the surroundings via heating and waves
• As the plane lands, the gravitational potential energy store will decrease