- #1

jumbogala

- 423

- 4

## Homework Statement

I'm doing a lab and getting very confused.

A cart is on a table. It is attached to a string which goes over a pulley. The pulley is on the edge of the table.

On the end of the string there is a mass. When the mass falls straight down, it pulls on the string and makes the cart accelerate too.

## Homework Equations

Mass of the cart = 1 kg (constant)

Trial 1: mass falling down: 0.1 kg & mass added to cart: 0.4 kg

Trial 2: mass falling down: 0.2 kg & mass added to cart: 0.3 kg

Trial 3: mass falling down: 0.3 kg & mass added to cart: 0.2 kg

Trial 4: mass falling down: 0.4 kg & mass added to cart: 0.1 kg

## The Attempt at a Solution

I am supposed to graph the acceleration of the cart vs. the pulling force. However, I am not sure what this graph should look like.

For trial 1, the pulling force would be (0.1 kg)*(9.81 m/s

^{2})=0.981 N, right? And the theoretical acceleration would be 0.981 N/(0.4 kg+1kg) = 1.962 m/s

^{2}.

However, if I graph a vs. F, I don't get a straight line, because the mass of the moving object is always changing. Is this right? In the book they make a big deal about the

**total**mass of the system being constant, so I'm wondering if that has something to do with it.