topic 3 conservation of energy

Question 1

change in gravitational potential energy =

Answer 1

mass x gravitational field strength x change in vertical height

Question 2

mechanical waste

Answer 2

• in mechanical processes ( i.e. where forces are involved on objects)
• energy transferred to it can cause a rise in temp
• so energy is dissipated to surroundings ( heat is transferred to air) and makes this process wasteful

Question 3

conservation of energy

Answer 3

• means that total energy of an isolated system remains constant
• a ‘closed system’ has no external forces acting on it
  i.e. no change in gravitational force, no electrostatic attraction, no external magnetic force

Question 4

what are two equations to calculate efficiency

Answer 4

• useful output energy / total input energy
• useful power output / total power output