a machine transfers energy from one place to another OR from one form to another
100
What are the units for work and power
Joules and Watts
100
what is the equation for Work
Work = force * distance
200
What are the two types of mechanical energy?
Kinetic and Potential Energy
200
a ball is dropped off a building. How does its potential energy at the top compare to its kinetic energy at the bottom of the fall.
They are the same.
200
What are the two parts of a lever
bar (axle) and folcrum
200
What is the source of all energy on Earth
The Sun
200
What is the equation for power
Power = work/time
300
What are the three types of Potential Energy?
Elastic, Chemical, Gravitational
300
An object is lifted by doing 200 J of work. How much potential energy does it have.
200 J
300
Define mechanical advantage
the ratio of force output to force input
300
What are the units for mechanical advantage and efficiency
MA has no units, Efficiency is %
300
What is the equation for gravitational potential energy?
PE = mass * gravity * height
400
Define potential energy.
Stored energy (answers may vary some)
400
A car has 5000 J of chemical energy in gasoline but only 3000 J of Kinetic energy as it drives. Does this violate the law of conservation of energy? Why or why not
No, energy is transformed into heat energy
400
Define efficiency
ratio of actual mechanical advantage to theoretical mechanical advantage
400
How is energy from coal traced back to the Sun
Coal is formed from decaying plant matter, plants get their energy from the sun
400
What is the equation for mechanical advantage?
MA = force output/ force input
500
Define Kinetic Energy
Energy in motion
500
In a swinging pendulum, where is the potential energy the greatest, where is the kinetic energy the greatest.
Potential, at the top of the swing
Kinetic, at the bottom of the swing
500
Why do some machines have less than 100% efficiency