What is the stopping distance of a car and what factors affect it? Lesson link What is the stopping distance of a car and what factors affect it?

Gravitational and Kinetic Energy Draw a line under last lesson’s work and write today’s title in your book... 31/12/2018 c/w Gravitational and Kinetic Energy

Developing Recall the nine forms of energy Learning Objectives Developing Recall the nine forms of energy Securing Recall and use the equation for calculating the energy of a moving object (KE= ½ x m x v2) and for gravitational potential energy (ΔGPE= m x g x Δ) Exceeding To be able to explain conservation of energy and relate this to a conversion of GPE into KE

Engage Do you remember GEEKS LuNCH? What are the nine types of energy represented by this acronym? Gravitational Potential energy Elastic Potential energy Electrical energy Kinetic energy Sound energy Light energy Nuclear energy Chemical energy Heat energy

For the next few slides, just draw a quick picture to help you remember and copy down the sentence for each Energy subheading Small explanation Any relevant picture!

Gravitational Potential Energy (GPE) If a mass (object) is lifted up, it will be gaining GPE. It has only potential energy which can be released when it’s dropped!

Elastic Potential Energy This potential energy is stored inside an elastic material when it is stretched. It is released only when the material is let go!

Electrical Energy This is the energy provided to, or carried by, an electron around a circuit!

Kinetic Energy This is basically described as movement energy, if an object is in motion, it has kinetic energy

Sound Energy If air particles are vibrating then this is known as sound energy. Lots of energy is wasted in this form.

Light Energy This is pure energy that is produced from any light producing (luminous) object

Nuclear Energy This energy is stored within the nucleus of atoms. When the nucleus is split, a huge amount of this energy is released

Chemical Energy Chemical energy is produced in reactions. It is the sort of energy we make by digesting food and the type found in batteries and fuel stores (coal etc..)

Heat Energy Heat energy, also known as ‘infra red’ is simply the energy released in the form of heat!

When do objects have the most gravitational potential energy? When an object is lifted up, it will gain gravitational potential energy. It’s called potential as it’s getting stored up. It’s only evident when you let the object drop! ΔGPE= mass x gravitational field strength x Δheight ΔGPE= m x g x Δh So the amount of the energy depends on three things: The mass of the object The strength of gravity The height it’s been lifted Δ means ‘change in’. Mass is in kg h is in m GPE is in J

Two 5kg dumbells lifted 1.2m So first let’s practice: How much gravitational potential energy would each of these objects gain if lifted by the given heights on Earth (remember on Earth, ‘g’ is 10m/s) 20J! A 1kg steak lifted 2m 120J! Two 5kg dumbells lifted 1.2m 60,000J! A 1200kg car lifted 50m

Try this more complex question: There are three sacks of flour, each labelled with a letter (A, B and C). Sack A is lifted 3m, Sack B is lifted 5m and Sack C is lifted 8m. Using the GPE they gained below, calculate the mass of each sack Sack GPE/J A 900 B 400 C 160 C A A= 30kg, B= 8kg, C= 2kg B

KE= ½ x m x v2 When do objects have the most kinetic energy? When an object is moving, it has kinetic energy. The faster it is going, the higher the energy! KE= ½ x mass x velocity2 KE= ½ x m x v2 So the amount of the energy depends on two things: The mass of the object The velocity of the object Mass is in kg V is in m/s KE is in J

So first let’s practice: How much kinetic energy would each of these objects have if they had these values of mass and velocity? A 1200kg car travelling at 8m/s 38400J! A 90kg bike travelling at 5m/s 1125J! 0J! A 2100kg rocket which is stationary

The law of conservation of energy means that Energy Transfer The law of conservation of energy means that “Energy is not created or destroyed, only TRANSFERRED or TRANSFORMED from one energy type to another” This makes sense really, think of a tennis ball being picked up (gaining GPE) and then being dropped. As it’s dropping all that GPE is being transformed into kinetic (movement) energy!

Exam Practice Susan drops a tennis ball and notices the following pattern when she takes a photo many times a second. Discuss the energy changes that are occurring as the tennis ball bounces in this way. 6 marks

Exam Corrections: Susan drops a tennis ball and notices the following pattern when she takes a photo many times a second. Discuss the energy changes that are occurring as the tennis ball bounces in this way. 6 marks Before the ball is dropped it has maximum GPE as it is high above the ground. As it’s released this GPE gets converted into KE as it falls. The kinetic energy increases as it nears the ground as it’s getting faster. Upon hitting the ground, this KE is then converted back into GPE (and again each time) as it rises above the ground. It’s getting less high each time because on each bounce it is transferring energy to surroundings as heat and sound

Developing Recall the nine forms of energy Learning Objectives Developing Recall the nine forms of energy Securing Recall and use the equation for calculating the energy of a moving object (KE= ½ x m x v2) and for gravitational potential energy (ΔGPE= m x g x Δ) Exceeding To be able to explain conservation of energy and relate this to a conversion of GPE into KE

A rollercoaster with a loop Independent Study Write two paragraphs, each explaining the energy transfers occurring in: A piece of coal burning to boil water that is turning into steam to turn a turbine A rollercoaster with a loop