Instruction Sheet - 3B SCIENTIFIC 1008539 Instrucciones De Uso

3B SCIENTIFIC ® PHYSICS

Instruction sheet

01/13 ALF
1. Description
Equipment set to demonstrate the law of the
lever, used in experiments on equillibrium and
beam-type model scales.
The equipment kit consists of a stand upon
which a lever arm is mounted on a ball bearing.
There are drilled holes in the middle of the arm
running along the arm's axis. These are used to
suspend weights from in order to shift the ful-
crum's position. A red and white block scale
permits a rapid reading of the lever arm's length.
A scale with pointer attached to the stand per-
mits precise display of the state of equilibrium.
2. Technical data
Length of lever:
Mass of lever:
Number of holes:
Separation of holes:
Set of weights:
Lever 1008539
The lever belongs to the class of simple ma-
chines. The machine we are normally dealing
with here is a straight or angled bar. The lever
can pivot around an axis (fulcrum) and utilize
forces operating at a distance from the fulcrum.
Each force results in a torque, which is all the
greater in magnitude, the greater the force and
the longer the force's line of action is to the rota-
tion axis (length of the arm). A lever with its ful-
crum at position O, upon which forces F and G
are acting, is in equilibrium, if the left hand
torque is equal to the right hand torque (law of
levers: force multiplied by the force arm equals
load multiplied by the load arm). The following
holds true for the forces F, G and the lever arm
lengths L
1 m
⋅
G L
1
0.458 kg
If the fulcrum of the lever is exactly between the
21
application points of the two forces, this is called
50 mm
a two-arm lever (Fig. 2), if the forces are located
10x 50 g
on the same side this is termed a single-arm
lever (Fig. 3).
1
1 Stand base
2 Stand rod
3 Scale
4 Pointer
5 Weights
6 Holder with ball bearing
and knurled nut
7 Lever arm
3. Operating principle
, L :
1 2
= ⋅
F L
2