energy efficiency - Sp3

Question 1

describe how energy is wasted in a car motor?

Answer 1

Wasted through sound + thermal

Question 2

How can friction be reduced?

Answer 2

via lubrication - or lubricants (oil)

Question 3

How can the heating energy transfer be reduced?

Answer 3

via insulation - (using cavity walls, double glazing windows)

Question 4

what is efficiency?

Answer 4

How good a device is at transferring energy input to useful energy output

Question 5

How can efficiency be increased?

Answer 5

by reducing wasted energy transfers so more of the input energy is usefully transferred.

Question 6

what is the equation for efficiency

Answer 6

useful energy transferred by device (J) / total energy supplied to device (J)

Question 7

what is the equation for gravitational potential energy?

Answer 7

mass x gravity x change in vertical height

Question 8

what is the equation for kinetic energy?

Answer 8

1/2 x mass x velocity squared

Question 9

what are the different factors effecting kinetic energy stored in an object?

Answer 9

mass and speed