Lesson 6

• Physics
• Middelbare school
• vwo
• Leerjaar 3

Chapter 3 — Energy

This lesson

•  The power of a wind turbine 
• Heat
• Specific heat capacity
• Worksheet

The power of a wind turbine

The power of a wind turbine

P=k⋅(v)​3​​

P: Power — Unit: Watt (W)

k: A constant — no unit

v: Speed of the wind — meters / second (m/s)

Practice exercise

Practice exercise

Section 2 Heating

What is heat?

What is heat?

What is heat?

• Thermal energy
  
• The internal movement of a substance on a molecular level
• Since heat is a form of energy, the unit of heat is Joules (J)

• Note: In all physical processes some amount energy is lost in the form of heat

Phet

Have a look at chapter 3, section 2 in the digital version of the book. Go over the part 'Experiment with a calorimeter

Specific heat Capacity

Specific heat capacity

The amount of energy required to heat up a certain amount of a substance a certain amount of temperature

Specific heat capacity

The amount of energy required to heat up a certain amount of a substance a certain amount of temperature

Examples:

• You need 4,18 Joule to heat up 1 gram of water 1 ºC
  
• You need 0,129 Joule to heat up 1 gram of gold 1º C

Specific heat capacity

Q: Heat in joules (J)

c: The specific heat capacity of a s substance (J/(g•ºC)

m: The mass of a substance in grams (g)

ΔT = T end  - T start : The temperature difference (ºC)

Q=c⋅m⋅ΔT

Q=c⋅m⋅ΔT

Homework check

• Section 1: Exercise 1, 2, 3, 4 and 7
  
• Section 2: Exercise 1, 2 and 3