# Energy 4.1

what is the name of energy store associated with a compressed spring?
elastic potential energy - when an object is squashed or stretched.
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what is the name of the energy store associated with a book high on a shelf?
gravitational potential energy - G.P.E
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what is meant by a closed system
a system where no energy is transferred into and out of the the energy store.
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in terms of energy stores what happens when you turn on a torch?
the energy is transferred from chemical energy in the battery to thermal energy in the surroundings via the bulb.
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describe the changes to an energy store when a child lifts a box from the floor to a shelf (2)
1 - increase in G.P.E of the box as its lifted 2- decrease in chemical energy in the child's muscles
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calculate work done work done when a force of 1500 n pulls a car the distance of 60m
work done = force x distance 1500 x 60 = 90000J
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a ball weighing 0.45kg is thrown vertically to a height of 3m ( the gravitational strength is 9.8) calculate the change of G.P.E.
G.P.E = mass x height x gravity 0.45 x 3 x 9.8 = 13.23J
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describe the energy store changes when a student stretches and releases a spring? (3)
1 decreases in students chemical energy in muscles 2 - elastic potential energy store increases as spring stretches 3-as springs released elastic p.e decreases and surrounding thermal energy increases.
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a driver pushes a broken down car but it does not move explain why work is not being done? (2)
1- because the car has not been moved a distance 2- and work is only done when a force moves an object by a distance.
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Describe the energy changes to stores when bungee jumper jumps off a bridge (4)
1-G.P.E decreases as jumoer gets closer to ground 2- kinetic energy increases as jumper picks up speed 3- when jumper reaches end of rope kineitc energy decreases and elastic potential energy increases 4- when jumper comes to a stop all energy is E.P
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give one example of a good thermal conductor
metal/water/copper
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identify which surfaces are best emitters of infrared radiation
matte black surfaces
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state three things that affect the rate of transfer of thermal energy through a material (3)
1- thickness of material 2-thermal conductivity 3- temperature gradient between materials
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explain why putting metal foil behind a radiator makes it more economical
1-inf
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## Other cards in this set

### Card 2

#### Front

what is the name of the energy store associated with a book high on a shelf?

#### Back

gravitational potential energy - G.P.E

### Card 3

#### Front

what is meant by a closed system

### Card 4

#### Front

in terms of energy stores what happens when you turn on a torch?

### Card 5

#### Front

describe the changes to an energy store when a child lifts a box from the floor to a shelf (2)