問題一覧
1
you exert an input force on a hammer. the hammer exerts a(n) force on the nail.
output
2
a dressmaker is cutting fabric. She applies 18 J of work to the scissors. The scissors apply 15J of work to the fabric as it cuts. What is the efficiency of the scissors?
83%
3
device made it more than one simple machine
output focre
4
power
work and divide; time
5
which one of the following is NOT an example of work being done?
the moon orbiting earth
6
a worker applies a force of 20N to pry open a window that has a resistance force of 500N. what is the mechanical advantage of the crowbar?
25
7
ratio of ouput force to input force
mechanical advantage
8
efficiency
output work and divide; input work
9
machines that are built by putting together two or more simple machines are call
compound machines
10
the force exerted by your foot on the pedal to ride your bike is an example of .
input force
11
work
force and times; distance
12
knife
wedge
13
leaf rake
lever
14
joe is using a crowbar to remove a tree stump. He applies 2066 J of work to the crowbar. The output work of the crowbar is 1240 J. what is the efficiency of the crowbar?
60%
15
force you apply to a simple machine
input
16
mechanical advantage
out put force and divide; input force
17
find the force needed to lift a 2000N rock, using a jack with a mechanical advantage of 10
200N
18
the amount by which a machine multiplies an input force is called the .
mechanical advantage
19
a winding mountain road is an example of a(n)___.
inclined plane
20
ideal mechanical advantage
radius of a wheel and divide; radius of axle