PHY $205$ GENERAL PHYSICS I Name$\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_$

Partner$$s Names$\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_$

Lab $2$ Constant Accelerated Motion

Objective:

Measure the linear acceleration of a small car propelled by a fan motor, and correlate the acceleration of the

car with the power of the fan motor.

Equipment:

Motion Sensor $1\mathrm{.}3$ m$-$long Aluminum Track USB interface

PASCO Capstone Fan Motor with rubber band PASCar

Introduction

The Pasco motion sensor is a sonar ranging device with a $15$ degree narrow beam. The sensor is connected via

a USB Link to a computer with Capstone software installed. Once connected, the sensor works by emitting

ultrasonic pulses and measuring the time it takes for the pulses to return as echoes from the target. With this

information, the computer program can measure position verses time in real$-$time, and then determine both the

velocity and acceleration of the cart.

As we learnt in the class lecture, the acceleration of a constantly accelerated object can be measured using the

slope of a velocity vs time graph. For an object with constant acceleration, this acceleration can be calculated

using

a $=$

$$

$$

$=$

$$

$$

$=$

rise

run

$=$ slope of the velocity vs time graph

In addition, to directly calculating this result, we

can also use a computer program to perform a

linear fit over the range of selected velocity vs time

data. In this case the program performs a regression

analysis using the experimental data, and

minimizes the separation between the data points

and a best$-$fit linear line. It is the slope of this bestfit linear line that is reported as the acceleration of

the cart. In addition, the program also returns a value

called the $($ correlation coefficient r

which is a measure of the linear correlation

between the two variables in the plot. The closer

this value is to $1,$ the better the fit.

Setup

$1.$ Turn the computer on and ensure that Windows has fully loaded before

starting step $2.$ Set the motion sensor to $$cart mode$$ as shown on the right,

and attach to an aluminum track by clamping it securely onto one edge of

the track.

$2.$ Connect the pin end of the motion sensor cable to the hole end of the

PASPort USB cable and the latter is then connected to one of the computer$$s $($not monitor$)$ USB ports.

$3.$ Open the PASCO Capstone program. Choose the Display icon that reads Sensor Data.

$4.$ The picture below shows a display of the program. The menu bar at the top of the window allows you to

save, open and close experiments. The associated toolbar allows quick access to important commands

including the undo and redo buttons.

$5.$ The data table window includes columns with selection buttons that allow you to display chosen data for the

physical variables measured by the sensor$.$ To select the data variable, click on the $<$ Select

Measurement$>$ box, and select the appropriate data variable. The choices with the motion sensor are

Position, Velocity, Acceleration and Time variables.

$6.$ The graph windows allow you to customize the axes by using the $$