p8 Flashcards
energy
the something that enables an object to do workulc
fulcrum
pivot point
joule
unit of work when 1 n exerted over a distance over i meter work= force x distance
potential
stored energy by virtue of its position
law of conservation of energy
in the absence of an external force, the momentum of a system remains the same
lever
a rigid bar with a pivot point
machine
a device used to change the applied ofrce and/or the direction of that force
mechanical advantage
ratio of output force to input force
power
rate at which work is done
pulley
a grooved wheel which cord is pulled through
watt
unit of power
work
energy transferred by force
Formula for work? -
force x distance (w=fd)
A person pulls a sled with the force of 20 N for a distance of 200 m, how much work was done?
4000 Nm
Same action above was done in 80s, how much power?
50 watts
Describe what happens to the amounts of PE and KE when you pick an object up and drop it.
Potential energy rises as you pick it up and kinetic energy stays the same. When you drop it the kinetic energy increases and the potential energy decreases. When it hits the ground the kinetic energy is back to zero.
Explain how no energy is actually lost when a campfire is burning. The fuel (wood) is transferred to what other types of energy?
The fuel turns into light energy and heat energy—the ones that we can feel and see.
The energy just changes forms. The energy is transferred into heat energy
A lever with the fulcrum moved closer to the load than the effort trades ___ for __.
distance; force
Show the 3 classes of levers.
First: fulcrum between load and effort
Second:load between fulcrum and effort
Third: effort between fulcrum and load
“I can’t lift 500 lbs one time but I can lift 10 lbs 50 times,” is talking about ________.
mechanical advantage
