Name
Period
Date
Newton’s Second Law of Motion
The Modified Atwood’s Machine
Acceleration vs. Force with constant Mass



Open the Data Studio file Newton’s Second Law.
Add the following masses to the cart.
2 – 5 g masses
2 – 20 g masses
1 – 50 g mass
3 – 100 g masses
1 – 200 g mass
1 – 500 g mass
=
=
=
=
=
=
0.010 kg
0.040 kg
0.050 kg
0.300 kg
0.200 kg
0.500 kg
Total mass on cart
=
1.100 kg
To keep the system mass constant, all mass must now stay
either on the string or in the cart!
Move 40. g = 0.040 kg from the cart to the end of the string for the first trial.

Don’t forget, the mass hanger adds 5 g = 0.005 kg to the hanging mass.
To calculate the Force:
Force = Fg acting on the hanging mass = mhanging x g = mhanging x  9.8 N 
kg 

Hanging
Mass
(kg)
Force
(N)
Trial 1
Trial 2
Trial 3
Average
Acceleration
(m/s2)
0
0
0
0
0
0
Acceleration (m/s2)
0.045
0.085
0.125
0.165
0.205
Calculate the Constant System Mass:
Constant System Mass = (1.100 kg) + (
total mass
on cart
kg) + (0.005 kg) =
mass
mass
of cart
hanger
kg
Newton’s Second Law – The Modified Atwood’s Machine
page 2
Acceleration vs. Mass with constant Force

Open the Data Studio file Newton’s Second Law.

Keep the force constant by placing 95 g = 0.095 kg onto the mass hanger which
with the 5 g = 0.005 kg mass hanger is a total hanging mass of 100. g = 0.100 kg
and leave it there for this half of the lab.

Start your first trial without any masses in the cart. Then change the System
Mass in 200. g = 0.200 kg increments by placing masses on the cart.
To calculate the System Mass:
System Mass = (
kg) + (
kg) + (0.100 kg)
Mass of cart
Added Mass Total Hanging
on Cart
Mass
Added
Mass
(kg)
System
Mass
(kg)
Acceleration (m/s2)
Trial 1
Trial 2
Trial 3
0
0.200
0.400
0.600
0.800
1.000
Calculate the Constant Force:
Constant Force = Fg acting on the hanging mass
= mhanging x g
= (0.100 kg) x  9.8 N kg 


=
N
Average
Acceleration
(m/s2)