Introduction
What is does m mean in K.E. = 1/2 m v2 and P.E. = mgh?
m = mass
The conservation of energy is a law of nature, which means...?
It cannot be defied in any way, shape, or form
What is the definition of potential energy?
The energy that is stored in an object because of its position relative to some zero position.
What is the definition of kinetic energy?
The energy of motion.
Who wrote the "Interrupted Pendulum"?
Galileo Galilei
What is v in K.E. = 1/2 m v2?
v = velocity
What IS the conservation of energy?
The law that energy cannot be created or destroyed, only converted or transformed
A 2 kg hammer is at a height of 0.4 m. What is it's PE?
2 * 9.8 * .4 = 7.84 Joules
What is the KE of a 1500 kg car going at suburban speed of 14 m/s?
1/2 * 1500 * 14 = 147 Joules
Once a pendulum is moving, it does not...?
twist or spin
What is h in P.E. = mgh?
h = height
What is a zero point in potential energy?
The reference point for the object in position
A 13000 g wrecking ball is hoisted at a height of 15 m. What is the PE?
1,911,000 Joules
A kid has a mass of 40 kg and is running at a velocity of 3 m/s. How much kinetic energy does he have?
1/2(40)*32= 80 Joules
Because the time period of a pendulum is constant, it can...?
Be used to tell time
What does "E" mean in K.E. = 1/2 m v2 and P.E. = mgh
E = Energy
What is the unit used for Energy?
Joules (kgm/s2)
If the Potential energy of fishing net is 3082.1 Joules and the net was hoisted at a height of 8.5 meters, what is the mass of the net?
3.0821/(9.8*8.5)=.037 kg
A 50 kg man's KE is 900 Joules. What is the velocity he is running at?
1/2(50)*62= 900 Joules
v=6
What year were pendulums added to clocks?
1660
What is g in P.E. = mgh?
g = acceleration due to gravity (9.8)
What is the definition of Energy?
The ability to exert a force causing displacement of an object
If the PE of a child at the top of a swing is 1881.6 Kilo Joules, and the child weighs 30 kg, what is the height of the swing?
1881.6/(30 * 9.8)= 6.4 m
A car has the KE of 968688 Joules and is moving at a velocity of 124 m/s. What is the weight of the car?
968688/(1/2*1242)= 126 Kg
What did Jean Foucault do with a pendulum?
He used the pendulum to prove that the earth rotates on its axis.