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50 questions
Any device that helps us do work is called.
A producer
A machine
An animal
A contraption
The 6 simple machines are...
Lever, nail, screw, pulley, wedge, wheel & axle
Hammer, inclined plane, screw, pulley, nail, wheel & axle
Lever, inclined plane, screw, pulley, wedge, wheel & axle
Inclined plane, diamond, pulley, wedge, metal, wheel & axle
Input and output forces are measured in...
Kilograms
Pounds
Newtons
Joules
The formula for finding the speed ratio is...
input distance / output distance
object slope / height
object slope / speed
output distance / input distance
____________________ is a force that opposes motion.
Angle
Twisting
Friction
Speed
The formula for calculating the Mechanical Advantage is...
Output Force / Input force = MA
Input force / Output force = MA
Direction x Angle = MA
Angle x Speed = MA
You are trying to move a heavy rock. The pulley system is 87% efficient, the inline plane is 56% efficient and the lever is 84%. Which machine should you choose?
Incline plane
Pulley
Lever
37 Newtons of force are required to lift a mass 3.5 meters above the floor. How many Joules of work is done?
12.95
129.5
1295
1480
Hydraulic systems use ________ to transfer force from one point to another.
Air
Liquid
Solid
Gas
Air is compressible and liquid is incompressible.
True
False
Which of these is not a simple machine?
Scissors
Screw
Wheel and axle
Pulley
Force is measured in:
Metres
Joules
g/cm3
Newtons
If the output (driven) gear is smaller than the input (driving) gear, the speed will
increase
be constant
decrease
there is not enough information
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
A machine with a mechanical advantage greater 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.
has no effect on speed or effort force
A machine with a mechanical advantage of 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.
does not affect distance or speed
A machine with a mechanical advantage equal to 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.
does not affect distance or speed
To increase the mechanical advantage of a lever
make sure the fulcrum is in the middle of the lever
move the fulcrum closer to the load
move the fulcrum closer to the person
use a bigger fulcrum
Jeff is a landscaping contractor and lifts a rock weighing 600 Newtons by wedging a board under the rock. Jeff weighs 150 Newtons and puts all of his weight on the lever. How much mechanical advantage did the lever provide to Jeff in lifting the rock?
0
2
4
0.25
What is the mechanical advantage of the lever shown?
10
0.1
50
250
What is the unit for measuring work?
Newton
Joule
Watt
meter
Two people shove on a wall with 100 N of force. The wall doesn’t move. How much work is done?
100J
100N
0J
0N
For work to be done on an object, the direction and force have to be going the same direction.
True
False
The _______ the force the _______ work is done
less, more
smaller, more
bigger, more
bigger, less
A simple machine reduces the amount of work needed to accomplish a task.
true
false
What is the efficiency of the following simple machine?
85%
3%
33%
39%
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 does friction produce that reduces efficiency?
heat
water
energy
work
_____________ is a measure of how much of the work is changed into useful work
Efficiency
Energy
Joule
Newton
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.
What do we call the gear connected to the input power source, such as a motor?
Driven Gear
Bigger Gear
Smaller Gear
Driving Gear
What do we call the gear connected to the output, such as a wheel or mechanism in a system?
Driving Gear
Driven Gear
Bigger Gear
Smaller Gear
When you have a system with a driving gear that is _______ than the driven gear, you will increase torque and decrease speed.
smaller
bigger
same size
thicker
Identify this simple machine
Lever
Wheel & Axle
Inclined Plane
Screw
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