Physics 1

Question 1

What is key about energy?

Answer 1

Energy cannot be created or destroyed. It can only be TRANSFERRED from one store to another.

Question 2

What are the 8 energy stores?

Answer 2

Kinetic,
Chemical,
Thermal,
Elastic Potential, 
Gravitional Potential, 
Electrostatic, 
Nuclear
Magnetic,
(You can merge magnetic and electrostatic to make electromagnetic)

Question 3

What are the pathways?

Answer 3

• Mechanical
• Heating
• Electrical
• Work done by force

Question 4

When energy is transferred, almost always some of the energy is transferred to the ______________ energy store of the surroundings.

Answer 4

-Thermal energy store

Question 5

How can energy be transferred?

Answer 5

Energy can be transferred mechanically, elastically, heating or by radiation.

Question 6

When a force makes things change it _____________________.

Answer 6

It mechanically transfers energy between different energy stores.

Question 7

What does friction do?

Answer 7

Friction transfers energy mechanically into the thermal energy of the object or the surroundings.

Question 8

What pathway is affected by weight?

Answer 8

-The mechanical pathway.

Question 9

What is another word for a mechanical energy transfer pathway?

Answer 9

-Work

Question 10

What is work?

Answer 10

Work is the energy transferred, when a force moves an object through an distance.

Question 11

What is the formula for work done?

Answer 11

W=fs

Question 12

What does W=fs stand for?

Answer 12

Work done= Force x distance moved in the direction of the force.

Question 13

What are the units for W=fs?

Answer 13

W = f x s

Joules (J)= Newtons (N) x Distance moved in metres (m)

Question 14

What is the formula for Gravtional Energy store?

Answer 14

Ep=mgh

Question 15

What does Ep=mgh stand for?

Answer 15

Ep=mgh

Energy potential= Mass x gravitational field strength x height

Question 16

What are the units for Ep=mgh?

Answer 16

Ep=mgh

Joules (J)= Mass (kg) x 9.8 (n/kg) x height (m)

Question 17

What energy store is the energy from the elastic store transferred to the most?

Answer 17

-The gravitational energy store

Question 18

What is the formula for the elastic potential store?

Answer 18

Ep = 1/2 k x e².

Question 19

When is energy transferred to the elastic potential energy store?

Answer 19

Energy is transferred when a spring is stretched or compressed.

Question 20

Work done = _______ potential energy

Answer 20

Work done = Elastic potential energy ( as long as the limit of proportionality is not exceeded.)

Question 21

What are the units for Ep= 1/2 k x e²?

Answer 21

Joules= 1/2 x n/m x extension (m)

If extension isn’t in metres, than convert to metres

Question 22

What does Ep = 1/2 k x e². stand for?

Answer 22

Elastic potential energy = 0.5 x spring constant x extension²

Question 23

What is power?

Answer 23

Power is the rate of energy transfer. It is how much energy is transferred by second.

Question 24

What is the formula for power?

Answer 24

P= w/t , Power= work done divided by time

Question 25

What is the unit of power?

Answer 25

Watts (W), One watt is one joule per second.

1w= 1 joule per second.

Question 26

What is the formula for Efficiency?

Answer 26

Efficiency= (useful energy out ÷ total energy in) X100

Question 27

What is the unit for efficiency?

Answer 27

Percent %