Energy transformations
Gravitational potential energy
Kinetic calculations
Potpourri
100
What type of energy transformation happens in a toaster?
Electrical energy --> heat energy
100
What is the gravitational field strength on Earth?
9.8m/s2 - commonly rounded to 10m/s2
100
What is the formula for calculating potential energy?
100
Where does about 70% of our planet's oxygen come from?
The ocean- algae
200
What energy transformation occurs in a solar panel?
Light/radiant energy --> electrical energy
200
What is the formula for gravitational potential energy?
Ep = mgh
200
A 2 kg ball is moving at 3 m/s.
What is its kinetic energy?
KE=0.5mv2=0.5×2×32
Answer: 9 J
200
The Seven Sisters constellation is also known as what? (in Aotearoa)
Matariki
300
A hydroelectric dam generates electricity. Name the energy transformations that occur from the water at the top of the dam to electricity being produced.
Gravitational potential energy --> kinetic --> electrical energy
300
A book with mass m = 2 kg is lifted h = 1.5 m. What is the gravitational potential energy of the book?
GPE= 30 J
Working:
PE=mgh=2×10×1.5=30J
300
A 2 kg object has 8 J of kinetic energy.
What is its speed?
about 2.83 m/s
300
Name three animals that create a shell.
Snails, whelks, turtles, mussels, crabs, oysters, clams...
400
Name the energy transformations in these pictures.
--> 
-->
Chemical potential energy --> heat and kinetic --> gravitational potential --> kinetic
400
A 2 kg object is held 5 meters above the ground. Calculate its gravitational potential energy.
PE=mgh
=2×10×5
=100J
400
A car has 8,000 J of kinetic energy and a mass of 1,000 kg.
What is its speed?
4 m/s
400
How old is Ms Andrews?
29
500
What is the energy transformation ? 
Gravitational potential --> kinetic energy
Bonus- what will eventually happen and why?
500
A rock dropped from a cliff has 96 J of gravitational potential energy. What is the value of kinetic energy the ball has when it just reaches the ground (ignoring air resistance)?
The value of kinetic energy is 96J
500
An object moving at 4 m/s has 16 J of kinetic energy.
What is its mass?
2 kg 
500
How many teeth does a average male great white shark go through in his lifetime?
20,000-30,000