Newton’s Second Law Pre-Lab

Modified Atwood’s Machine What variables affect the acceleration of an object?

Acceleration

Net Force

Hanging mass (B)

Mass of cart (A)Mass

Friction?

Angle of track?

A B

gAF

NF

gBF

gAN FF

gBF gmF BgB

The track is tilted so that the cart moves with constant velocity

when given a small push.

D

I

ISystem Mass

A

B

Newton’s Second Law Pre-Lab

Purpose: To create graphical and mathematical representations of the relationship between the acceleration, the net force, and the mass of a modified Atwood’s machine.

Newton’s Second Law

Mass can be measured with the electronic balances around the room.

To measure the acceleration you must use Data Studio and the motion detector to find the slope of the velocity vs. time graph.

Open the Data Studio file Newton’s Second Law.

Add the following masses to the cart.

Newton’s Second Law Pre-Lab

1 – black bar mass = kg

2 – 5 g masses = 0.010 kg

2 – 20 g masses = 0.040 kg

1 – 50 g mass = 0.050 kg

3 – 100 g masses = 0.300 kg

1 – 200 g mass = 0.200 kg

Total mass in cart = kg

Acceleration vs. Force with constant Mass

To keep the 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.

Newton’s Second Law Pre-Lab

How can we change the force but keep the system mass constant?

A

B

Acceleration vs. Force with constant Mass