Types of Energy
The ability to do work is called:
Energy
An energy transformation occurs when a form of energy changes to another energy form in the same object
True
A torch uses chemical energy from a battery and transforms it into which form of energy?
Light Enery
Whenever a moving object experiences friction, some of its kinetic energy is turned to
A) mechanical energy
B) potential energy
C) thermal energy
D) light energy
C) Thermal
a bicycle uses 20J of energy, however, only 15J of that energy is used to move the bike forwards
calculate efficiency
efficiency = 15/20 x 100 = 75%
Give an example of kinetic energy
Riding a bike, walking, running
An energy transfer occurs when the form of energy remains the same type but is moved from one object to another
True
when energy is transformed there can be waste energy, what is the common types of waste energy?
Heat and Sound
Which of these is not an example of chemical energy?
A) Food
B) Petrol
C) Batteries
D) Light bulb
D) Light bulb
a vacuum uses 150J of energy. 10J is wasted in sound. Calculate efficiency
150 - 10 = 140J
140/150 x 100 = 93.3%
Define potential energy
The energy stored in an object
The formula to calculate kinetic energy is
Mass × Gravitational acceleration × Height
False - correct formula is
1⁄2 × Mass × Velocity-squared
name the forms of energy a microwave transforms
electrical into thermal/heat
What is the Law of Conservation of Energy?
Energy cannot be created nor destroyed in any chemical reaction. It can only be changed from one form to another.
what is energy efficiency always written as...
a percantage
List 8 different types of energy
Potential, Kinetic, Thermal, Sound, Light, Nuclear, Gravitational, Mechanical, Electrical, Magnetic, Elastic, Chemical
Gravitational acceleration is approximately 8.9 m/s2
False - Gravity = 9.81m/s2
give an example of chemical energy transforming into mechanical energy
a battery powering a toy
food giving you energy to walk, ride a bike or move
etc.
What energy transformations take place when a battery-operated radio is in use?
A) Electrical to chemical to light
B) Sound to chemical to mechanical
C) Chemical to electrical to sound
D) Light to electrical to thermal
C) Chemical to Electrical to sound
what is the formula for energy efficiency
useful output/total input x 100
Give 1 example for the following energy types:
Light, electrical & chemical
Sun, phone charger/light bulbs, petrol in a car
A plant turns thermal energy from the sun into chemical energy during photosynthesis is an example of energy transfer
False - example of energy transformation
how well one type of energy transforms into another is called...
energy efficiency
Which of the following energy transformations occur when a lamp that is plugged into a wall socket
A) Chemical to light
B) Electrical to light
C) Electrical to chemical
D) Chemical to electrical
B) Electrical to Light
how would you calculate wasted energy?
wasted energy = total input - useful output