# DO NOW Q1. Explain the law of conservation of energy.

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DO NOW Q1. Explain the law of conservation of energy.
Q2. List all different types of energy

DO NOW (ANSWERS) Q1. Explain the law of conservation of energy. Energy can neither be created nor destroyed. Energy is always changing from one kind to another. The total energy of an object never changes. Q2. List all different types of energy: Electrical energy, light energy, potential energy, sound energy, heat energy, kinetic energy, nuclear energy

Today’s SLO’S Name the different forms of energy
Understand conservation of energy Recognise different forms of energy in an energy transfer Read NMS2 from page 32-33, answer all the questions + stretch yourself

Energy P 33 (Answers) Suitable examples
Energy cannot be created or destroyed – it can only be changed from one form to another. Chemical PE (food) → elastic PE → kinetic E P E P Ek → EP E k EP → Ek

Energy P 33 (Answers) (a) electrical → kinetic → sound (b) radiant (radio waves) + electrical → kinetic → sound (c) chemical PE → kinetic (d) no change of energy type. (e) chemical PE → kinetic + sound→ gravitational PE → kinetic → heat + sound (when the shuttle lands on the ground)

Stretch Yourself: 33 Q1. Energy transformation is an object that has the energy change from one type of energy to another, and energy transfer is a type of energy that goes from one object to another.

Q2. A moving aircraft has momentum, which is mass × velocity and is a measure of the effort needed to stop it moving. The same aircraft also has kinetic energy ( Ek=1/2xmxv2), which is related to mass × velocity squared. Also, because it has climbed above the Earth's surface, it has acquired additional gravitational potential energy which, in this case, is weight × height gained. ( Ep=mxgxh)

Stretch Yourself 33 The yo-yo has a certain amount of potential energy (energy of position). This potential energy takes two different forms: The yo-yo is held up in the air, giving it the potential to fall to the ground. The yo-yo has string wound around it, giving it the potential to spin as it unwinds. When the yo-yo is released, both forms of potential energy change to kinetic energy. The yo-yo spool falls straight to the ground, which builds a certain amount of linear momentum (momentum in a straight line). At the same time, the string unwinds, and the spool spins, which builds angular momentum (momentum of rotation). When the yo-yo reaches the end of the string, it can't fall any farther. But, because it has a good deal of angular momentum, it will keep spinning.

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