P1

Question 1

Conservation of energy

Answer 1

Energy cannot be created or destroyed

Question 2

Dissipated energy

Answer 2

The energy that is not usefully transferred or stored

Question 3

Effeciency

Answer 3

Useful energy transferred by a device + total energy supplied to the device

Question 4

Hookes law

Answer 4

The extension of the spring is directly proportional to the force applied

Question 5

Power

Answer 5

The energy transformed or transferred per second

Question 6

Spring constant

Answer 6

Force per unit extension of a spring

Question 7

Work

Answer 7

Word done (joules)=force(N)x distance moved in the direction of the force (m)

Question 8

Kinetic energy equation

Answer 8

Kinetic energy= 0.5 x mass x (speed)^2

Question 9

Equation for elastic potential energy

Answer 9

Elastic potential energy= 0.5 x spring constant x (extension)^2

Question 10

Equation for gravitational potential energy

Answer 10

GPE= mass x gravitational field strength x height

Question 11

Change in thermal energy equation

Answer 11

change in thermal energy = mass × speci f ic heat capacity × tem perature change

Question 12

Power equation

Answer 12

power = energ y transferred/ time

Or

Power= work done/ time

Question 13

Ways of reducing unwanted energy transfers

Answer 13

Lubrication to stop friction, thermal insulation

Question 14

Energy effeciency equation

Answer 14

Effeciency= useful output energy transfer/ total output energy transfer

Or

Effeciency= useful power output/ total power input