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WorksheetsCh.3 Work and Machines
Total questions: 23
Worksheet time: 14mins
For work to be done on an object
some force need only be exerted on the object
the object must move some distance as a result of a force
the must move, whether or not a force is exerted on it
the object must not move
If you exert a force of 20 newtons (N) to push a desk 10 meters (m), how much work do you do on the desk?
200 joules
30 joules
10 joules
100 joules
The mechanical advantage of a machine is the number of times a machine increases
the distance an object is moved
the amount of friction
the change in direction
the force exerted on the machine
A simple machine that might be thought of as an inclined plane that moves is a
lever
wheel and axle
wedge
pulley
One example of a compound machine is a
door
pliers
bicycle
shovel
The ideal mechanical advantage for an inclined plane is equal to the length of the incline divided by the
mass of the incline
slope of the incline
height of the incline
angle of the incline
How can a hockey stick be considered a machine?
it increases force
it multiplies distance
it changes direction
it reduces friction
If tight scissors have an efficiency of 50 percent, half of your work is wasted due to
the output force
the input force
friction
changes in direction
Power is measured in units called
joules
pounds
watts
newtons
The wedge, screw, and lever are all
simple machines
compound machines
found in the human body
100 percent efficient
The force exerted by a machine is called the output force
True
False
A wheel and axle is a compound machine
True
False
The ideal mechanical advantage of a wheel and axle is the radius of the wheel times the radius of the axle
True
False
You do work on an object when you lift it off the floor onto a shelf
False
True
Joule is the rate at which work is done
False
True
A wheel and axle is a simple machine
True
False
The ideal mechanical advantage of a wheel and axle is the radius of the wheel divided by the radius of the axle
True
False
Power is the rate at which work is done
True
False
A screwdriver is a simple machine called a(n) ________ ___ _______
(a)
A device that is twice as powerful as another can do (a) the amount of work in the same amount of time
A machine makes work easier by multiplying force or (a) , or by changing direction
A ramp in a parking garage is an example of a simple machine called a(n) _________ _________
(a)
Power is equal to (a) divided by time
