Vocabulary
The ___ of an object increases as it moves faster.
kinetic energy
stored energy that depends on the position of an object relative to Earth's surface
Gravitational Potential Energy
When you ride a bike, what is the source of energy that you use to pedal?
Chemical energy from food you eat.
a slide at a park is an example of which simple machine?
A student pulls out her chair in order to sit down. The student pulls the chair 0.75m with a force of 20N. How much work does she do in the chair?
15J
The product of force and distance
work
energy stored in and released from an atom's nucleus
nuclear energy
the transfer of energy that occurs when a force makes an object or particle move.
work
an ax is an example of which simple machine?
wedge
A student lifts a bag from the floor to his or her shoulder 1.2m above the floor using a force of 50N. How much work does the student do on the bag?
60J
a ___ is made of more than one simple machine
complex machine
Where is energy stored in fossil fuels?
it is stored in the bonds between carbon atoms. (chemical energy)
how is putting a book in your backpack an example of work?
the book moves down into the bag, which is the same direction as the force you apply.
scissors are an example of a complex machine. Which two simple machines make up scissors?
lever, wedge
A bird pulls a worm from the dirt with a force of 0.05N a distance of 0.07m. How much work is done on the worm?
0.004J
the ratio of output work to input work
efficiency
Some electromagnetic waves can travel through solids, liquids, gases, and vacuums. What kind of energy is carried by electromagnetic waves?
radiant energy
force and distance
how can machines make work easier?
changing the distance, increasing output force, or changing direction of force.
Lisa applies a constant force of 30N as she pushes a dresser 3m. How much work did Lisa do on the dresser?
90J
seismic energy
Describe the transformation of potential energy to kinetic energy to electric energy in a hydroelectric plant.
water (potential) falls down moving turbines (kinetic) to become electric energy.
heat is generated when _______ moves from a region of higher temperature to a region of lower temperature.
thermal energy
How does Newton's Third Law apply to simple machines?
Mark applies a constant force of 25N as he pushes a desk. In total, he moves the desk 12m. How much work did Mark do?
300J