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WorksheetsMachines, Mechanical Advantage & Efficiency
Total questions: 30
Worksheet time: 3hrs 30mins
A box of weight W is lifted by a force F using a lever as shown below.
What is the mechanical advantage of the lever (MA=Input Distance/Output Distance)?
0.5
2
3
6
Using a lever, Joe is able to lift a 10,000 N car off of the ground with a force of 1000 N. What is the mechanical advantage of the lever (MA=Output Force/Input Force)?
1
10
100
1000
A pulley has a mechanical advantage equal to 1 because.....
The output force is larger than the input force.
The output force is smaller than the input force.
The output and input force are equal, but the direction of the force changes.
None of the above.
A machine's _______________ is determined by comparing the input and output forces.
efficiency
mechanical advantage
work
friction
The _________ of a machine is always less than 100%.
mechanical advantage
friction
force
efficiency
How does using a jack to lift a car make work easier?
it changes the size of the foce
it changes the distance the force acts
it changes the direction a force acts
none of the above
Why can mechanical efficiency never be 100%?
No machine is strong enough.
Machines are too big to allow for 100% efficiency.
It can be 100%.
Some energy is lost in the form of heat/sound due to friction.
What happens to the overall efficiency of a machine as I add more machines?
For each simple machine you add, the overall efficiency increases because it gets faster.
For each simple machine you add, the overall efficiency decreases.
The overall efficiency is divided in half for every simple machine you add.
There is no connection.
the amount of work you do when you exert one Newton of force to move the object one meter
joule
newton
meter
output force
the rate at which work is done
power
work
machine
efficiency
a machine that utilizes two or more simple machines
compound machine
machine
wedge
screw
a simple machine made of a grooved wheel with a rope or cable wrapped around it
pulley
wheel and axle
screw
lever
a simple machine made of two circular or cylindrical objects fastened together that rotate about a common axis
wheel and axle
pulley
screw
compound machine
A machine with a ratio less than 1:
multiplies the input force so the machine would be good to help move heavy objects.
does not multiply the force, but increases distance and speed.
is good for lifting and moving objects quicker.
Is not good for lifting or moving objects quicker.
Real machines:
actually exist
have an efficiency less than 100%
lose energy due to friction
all are correct
which lever type is a wheel barrow?
type 1
type 2
type 3
none of them
the mechanical advantage of a wheel and axle is...
wheel diameter / force
wheel diameter / axle diameter
axle diameter / wheel diameter
What is the mechanical advantage of a pulley system that looks like this?
5
8
1
2
What is effort (input) force?
the force one exerts on a machine
the force which an effort force must overcome in order to do work on an object via a simple machine.
the force the machine exerts on a object
the output work times the input distance
What is resistance (output) force?
the force required by a machine in order to accomplish work (the force you put on the machine)
The force that is exerted by a machine
the force the machine exerts on a object
the output work times the input distance
