Definitions
The ability to do work
What is energy?
W=Fd
What is the equation for work?
the amount of work done when 1000 newtons acts through a distance of 3.75 meters
3750 J
Potential energy + kinetic energy on the macro scale for an object/system
What is mechanical energy?
The SI unit for work and energy
What is the joule?
P=W/t
What is the equation for power?
The power used to lift a 70-kg box 5 meters upward against gravity (use g=10 m/s2), in a time of 3.5 seconds
1000 W
The energy of motion
What is kinetic energy?
Force times distance
What is work?
PE=mgh
What is gravitational potential energy?
The kinetic energy of a 4.0-kg cannonball traveling at 300 meters per second
180,000 J
The energy of position
What is potential energy?
Work divided by the time to do that work
What is power?
KE=1/2 mv^2
What is the equation for kinetic energy?
The gravitational potential energy of a 0.40-kg football when it is 12 meters above a playing field. Use g=9.81 m/s2. Answer to 2 sig figs.
47 J
Find the elevation of a 50.0-kg child if they gravitational potential energy is 1005 joules. use g=9.81.
2.05 m
When you do work on an object, you change its total energy.
What is the work-energy theorem?
Etotal = PE + KE
What is the conservation of energy equation?
or
what is the law of conservation of energy?
The theoretical velocity of any object dropped from a height of 50.0 meters, just before impact with the ground. (From the lab activity, you derived v = the square root of 19.62h.)
31.3 m/s
must be rounded to 3 sig figs as above
The velocity of a 1300.0-kg sportscar if its total kinetic energy is 1.00x106 joules.
39.2 m/s