Planning for the activity

[admin]

Time Requirements
• One class period.
Materials Needed
For each group:
• balls, set of 2
• ball, tennis
• c-clamp
• ruler, flexible plastic, 30 cm
• ruler, metric, mm marking
• washers, metal, 3/4"
Advance Preparation
and Setup
Identify the particular combination of flexible rulers
(or plastic strips) and weights (coins or metal
washers) which will serve as force meters. Identify a


 

PAGE 31 CONTINUED

means of preventing the weights from slipping off the
bent plastic strip, such as a lightweight cardboard
“lip” taped to the plastic strip.
Also identify the set of objects to be accelerated;
either balls of about the same diameter but having
different masses or laboratory carts which can be
loaded to vary the mass would work. If possible, have
at least three objects of different masses available for
each group.
Try for yourself the calibration procedure and the use
of the force meter to accelerate objects in advance of
class. You may need to try different sizes of coins or
metal washers to find a kind which will produce a
reasonable amount of bend in the ruler for a 4-washer
load while at the same time providing a reasonable
amount of acceleration when the smallest and largest
objects are pushed using the smallest and largest
forces.