Grove Science Midterm; Force and Work
moving
An object that has kinetic energy must be...
false
T-F a machine can save time or work
false
T-F a watt is equal to equal to the amount of work that is accomplished when a force of one Newton moves an object a distance of one meter
false
T-F the effort arm of a lever is the part of the lever that resists the applied force
false
T-F you always get less out of a machine that you put in due to the force of gravity.
twice as much work
a 1000-kg car are hoisted the same distance in a gas station. Raising the more massive car requires...
40J
a bow is drawn so that it has 40J of potential energy. When fired, the arrow will ideally have a kinetic energy of...
power
a job is done slowly, while an identical job is done quickly. Both jobs require the same amount of work, but different amounts of...
second class lever
a lever in which the fulcrum and the effort are on opposite sides with the resistance located between the fulcrum and lever.
third class lever
a lever in which the fulcrum and the resistance are at opposite ends with the effort located between the fulcrum and resistance.
first class lever
a lever in which the resistance is at one end and and the effort at the other with the fulcrum somewhere between the two.
three parts
a lever is composed of how many parts?
at the opposite end of the resistance
in the third class lever, the fulcrum is located...
550 ft/Lbs
one horsepower is equal to how much work per second?
746 watts
one horsepower is equal to...
the work input must theoretically equal the work output
the Law of Machines states...
energy may not be created or destroyed but it can be changed from one form to another
the Law of the Conservation of Energy states...
energy
the ability to do work
effort
the applied force exerted to overcome the resistance
work
the exertion of a force through a distance to overcome motion
resistance
the force that must be overcome in doing work?
resistance
the force which must be overcome in doing work, or the opposition of a substance to the flow of electrons.
fulcrum
the point on which a lever is supported and free to rotate is called?
dependent on the mass of the barbell
the power expended when a barbell is raised 2.0 m in 2 s is...
work
the result of the exertion of a force through a distance is?
location
an object that has potential energy may have this energy because of its...
gain force, increase speed, increase distance, and change direction
first class levers may
gain, increase distance, and increase speed
first class levers may...
twice the usual power output
if you do work on an object in half the time, your pwer output is...
twice as much work
if you push an object twice as far while applying the same force, you do...
at all
if you push for an hour against a stationary wall, you do no work...
gravity, molecular attraction, and friction
what are types of resistance?
2nd class
what class lever is a wheelbarrow?
3rd class
what class lever is your arm?
work and time
what determines power?
lifting a bag of groceries
what is an example of work being done on an object?
1st class
what kind of lever is a small child's teeter-totter?
force and distance
what must work contain?
wedge
what type of machine is an axe blade?
heat
when a car is braked to a stop, its kinetic energy is transformed to...
twice as much
when an object is lifted 10 m, it gains a certain amount of potential energy. If the same object is lifted 20 m, its potential energy gain is...
force
when using a second-class lever what will you gain?
both require the same amount of work
which requires more work: lifting a 50-kg sack vertically 2 m or lifting a 25-kg sack vertically 4m?
Watt
who was the originator of the concept of horsepower?
