Energy
the energy of either an object in motion or the energy that is stored in objects by their position
Types: Kinetic & Potential energy
What is the kinetic energy of a 158 kg turtle swimming at 0.42 m/s?
KE = 13.94 J
A box is pushed with a force of 10 N and the box travels 5 m. What is the total work?
W = 50 J
The Sun
Nuclear
Potential energy
GPE = mgh
What is the law of conservation of energy?
Energy can be neither created nor destroyed, only changed in form.
Determine the gain in gravitational potential energy when a 4 kg block is raised 18 m.
It took 20 J to push a box 2 m across the floor. With what force was the box pushed?
F = 10 N
Light rays through space
Electromagnetic Radiation
Kinetic Energy
KE = (1/2) (m) (v^2)
Energy stored in chemical bonds
An aircraft is taking a group of skydivers up into the air. Evan is dressed in his parachuting gear, which brings his mass to a total of 90 kg. The aircraft takes the group to a height of 5,000 m before the jump. How much GPE does Even gain?
GPE = 4,410,000 J
A woman lifts a bucket of water 61.7 cm above the ground. If the bucket of water has a mass of 17.5 kg, how much work does the woman do?
W = 105.8 J
The vibration from a guitar
Acoustic/sound
Fw = mg
What is elastic energy?
Energy stored in objects that have been stretched
The largest sea turtle found in the US has a mass of 860.24 kg. If the GPE associated with the turtle as it was being lifted onto a ship was 20,320.7 J, how high above the water was the turtle?
h = 2.41 m
A man lifts a bucket of sand 75 cm above the ground. If the bucket of sand has a mass of 12,500 g, how much work does the man do on the bucket?
W = 91.9 J
Energy from heat
Thermal
All Equations of Work
W = Fd
W = mgh
W = (Fw)(h)
Name all the forms of energy
Potential, Kinetic, Chemical, Electrical, Thermal, Elastic, Nuclear, Acoustic, Electromagnetic Radiation
A seagull with 5.6 J of KE is flying at 4 m/s. What is her mass in kg?
m = 0.7 kg
An elevator in a skyscraper has a mass of 904.9 kg. Inside the elevator are three people whose masses are 67.8 kg, 55.9 kg, and 75.1 kg. Determine how much work the elevator motor does in lifting this elevator and the people inside it from the ground floor up to the 47th floor, 564 ft above the ground floor. Assume there is no friction and state the result in J.
W = 1,860,000 J
Energy stored in objects
Potential
Energy Efficiency
((Energy out)/(energy in)) x 100%