PASCO ME-9430 Dynamics Cart with Mass - Manual (Page 11)

012-04840E Dynamics Cart
7
®
– Balance (SE-8723 or equiv.)
Purpose
In this lab, a small mass m will be connected to the Dynamics Cart by a string as shown in
Figure 3.1. The string will pass over a pulley at the table’s edge so that as the mass falls the
cart will be accelerated over the table’s surface. As long as the string is not too elastic and there
is no slack in it, both the falling mass and the Dynamics Cart will have the same acceleration.
The resulting acceleration of this system will be determined experimentally, and this value will
be compared to the acceleration predicted by Newton’s Second Law.
Theory
The cart will be released from rest and allowed to accelerate over a distance d. Using a stop-
watch, you will determine how long it takes, on average, for the cart to move through the
distance d. An experimental value for the cart’s acceleration a can be determined from:
Assuming that the tabletop is truly horizontal (i.e. level), Newton’s Second Law ( F = ma)
predicts that the acceleration of this system will be:
Procedure
1. Set up the pulley, cart, and a bumper of some sort to prevent the cart from hitting the pulley at
the end of its run. Add the following masses to the bed of the cart: 10 g, 50 g, 500 g and two 20
gram masses.
2. Carefully level the table until the cart has no particular tendency to drift or accelerate in either
direction along its run.
3. Put a loop in one end of the string and place this loop over the spring-release trigger on the
Experiment 3: Newton's Second Law
(Predicting Accelerations)
Figure 3.1
EQUIPMENT NEEDED:
– Dynamics Cart (ME-9430)
– Pulley and pulley clamp (ME-9448)
– Mass set (SE-8704)
– Stopwatch (SE-8702)
– String
– Paper clips
– Block (to act as bumper)
d = at 2 which leads to: a = (Experimental Value) 2 d
Trigger
Paper clips
a = or
F
net
M
TOTAL
a = ( ) g (Theoretical Value)
m
M
TOTAL
Bumper block
1
2
t 2