Work, Force & Distance
What is the equation to find the amount of work put into something?
Work = Force x Distance
True or false: Efficiency is always more than 100 percent.
False.
What is impact energy?
A measure of the work done to fracture a test specimen.
A 3 pound box being held 3 feet above the ground. Kinetic or potential energy?
Potential
How many simple machines are there? Name them.
A mule pulls a cart of milk 10 meters with a force of 50 newtons. Calculate the work done by a mule.
500 J
How does friction affect efficiency?
Friction reduces efficiency because when two surfaces slide past each other, friction resists their motion, and in real machines, some input work is always used to overcome friction
What is Resistance Energy?
a measure of how much voltage an electrical element needs in order to increase the electric current.
What is the difference between kinetic & potential energy?
Kinetic: Energy of an object or a system's particles in motion
Potential: Stored energy in an object or system by virtue position or arrangement of parts
What is Mechanical Advantage? What is the formula for it?
MA = IF/OF
True or False: In physics, the use of force to move an object is called distance.
False
What is the formula for power?
P = Work/Elapsed Time
What is the reciprocal of resistivity?
Conductivity
What type of energy is a rubber band?
Kinetic & Potential
True or False: The input force will always be greater than the output force.
True!
The amount of work done depends on the ______.
Amount of force & distance of which an object moves.
What is the formula for efficiency?
Output/Input
What is the unit of resitivity?
Ohm-meter
What is the kinetic energy formula?
K.E = 1/2 m v²
What type of energy do machines use?
Mechanical Energy
A weightlifter is holding a 300 pound barbell at height of 3 feet off the ground. How much work is he performing?
0 joules
What is the formula for friction?
F = coefficient of friction x normal force
Which of the following material has resistance almost equal to zero? semi-conductors, conductors, insulators or superconductors?
Superconductors
What is the potential energy formula?
U = mgh
u - gravitational energy
m - mass
g - gravitational field
h - height
What form of energy do machines use?
Kinetic Energy