• The principle of conservation of energy?is a law of Physics which always applies to a?closed system

• To apply conservation of energy, heat losses are usually ignored during the calculation stage
• In reality there are always some energy losses from the system
  • These should be mentioned when comparing calculated, ideal values to real-life situations

• Conservation of energy is often applied in questions about exchanges between?kinetic energy?and?gravitational energy
• Common examples include:
  • A swinging pendulum
  • Objects in?free fall
  • Sports such as skiing or skydiving where gravity is causing motion and few drag forces apply

• The gravitational potential energy stored initially is transferred to kinetic energy, or vice versa
• This allows either;
  • Final velocity to be found from the distance the object moved, or
  • Height of a drop from the final velocity

Step 1: Write down the known quantities

• • Vertical height,?h?= 750 sin 25°
  • Ek?= 0.85?Ep

   

Step 2: Equate the equations for?Ek?and?Egrav

Ek?= 0.85?Egrav

??mv2?= 0.85 ×?mgh

Step 3: Rearrange for final speed,?v

Step 4: Calculate the final speed,?v