The Impact of Constant Force

Figure 1

In this experiment you will explore the impact of constant force on a cart. The force of gravity will be applied to the cart by means of a string suspended over a pulley and connected to a hanging weight (see Figure 1).

According to Newton's Second Law, applying a constant force to a body yields a motion with constant acceleration.

The cart's velocity will be monitored using the Smart Pulley sensor.

einstein™Tablet+ with MiLAB or Android/iOS Tablet with MiLAB and einstein™LabMate Smart Pulley sensor Dynamic Track Dynamic Cart

Weight (100 g) String

1.

Launch MiLAB (

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Assemble the Smart Pulley sensor by mounting the pulley on the Photogate sensor with the rod provided.

Mount the Smart Pulley sensor on one end of the track using the pulley mounting bracket.

Connect the Smart Pulley sensor to one of the ports on the einstein™Tablet+ or einstein™LabMate.

Position the cart at the other end of the track.

Attach a string to the cart.

Attach a 100 g weight to the other end of the string.

Pass the string over the pulley.

Level the track and adjust the Smart Pulley height so that the string is parallel to the track.

Make sure that only the Smart Pulley sensor is selected.

Program the sensors to log data according to the following setup: Smart Pulley Sensor Rate:

25/sec

Duration:

4 Sec

Note: Make sure that only the Smart Pulley is selected and not the Photogate.

1.

Hold the cart at the end of the track.

2.

Tap Run (

3.

Release the cart.

4.

Tap Stop (

5.

Save your data by tapping Save (

) on the upper toolbar. ) on the upper toolbar as the hanging mass reaches the floor. ) on the upper toolbar.

Velocity (m/s)

Figure 2

For more information on working with graphs see: Working with Graphs in MiLAB. 1.

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Discuss the resulting graph. Does it agree with Newton's Second Law of Motion?

What can be said about the velocity changes over equal time intervals?

Fit a straight line to your data that passes through your data points: a. b. c.

Tap the Function button (

).

Tap the Linear function from the Curve Fit menu.

The linear fit to the data selection will appear on the graph and the fit equation will be displayed below the x-axis.

The slope of the linear fit line represents the acceleration of the cart.