Advanced Physics Through Inquiry 1 Teacher Guide

(PS-2848)

Teacher guide featuring 15 labs designed for Advanced Placement Physics 1.

Work and Kinetic Energy

Lab Summary

Students use a photogate and dynamics system to investigate the relationship between the change in kinetic energy of an object experiencing a non zero net conservative force and the work done by that net force on the object, and then use their data to establish a measurement-based relationship between work and kinetic energy.

Theory

How is the work done on an object by a non-zero net conservative force related to the change in that object's kinetic energy? Investigate the relationship between the change in kinetic energy of an object experiencing a non-zero net conservative force, and the work done by that net force on the object. Establish a measurement-based relationship between work and kinetic energy.

Method

Students use a cart and track system to show that the change in kinetic energy of a cart as it rolls down an inclined track is equal to the work done on the cart by gravity to displace it down the track. To show this, students release a cart on an inclined track from various positions and measure its speed and displacement at the bottom of the track. Assuming that the initial speed of the cart just as it was released was zero, students use their cart mass m and speed v measurements to calculate the change in kinetic energy (ΔK = 1/2mΔv2) of the cart as it traveled from the point where it was released to the bottom of the track in each trial. Students then use the displacement d, the angle θ between the track and the downward force from gravity, and the force F due to gravity (F = mg) acting on the cart to calculate the amount of work W done by gravity to displace it (W = Fdcos θ). Students' calculated values for the work done by gravity on the cart and the cart's change in kinetic energy should be nearly equal in each trial. From this, students are expected to ascertain that the work done on the cart by gravity to displace it down the track is equal to the change in the cart's kinetic energy after being displaced.

Sensors / Equipment Used:

Smart Gate

(PS-2180)

Photogate that can be connected to any PASPORT interface, has auxiliary port to daisy chain gates, double beams for accurate speed measurement, and a special photogate tape slot.

Photogate Brackets (2 Pack) -- IDS

(ME-9806)

The Photogate Bracket is designed to attach Photogate Head to PAStrack and Curved PAStrack.

PAScar (Set of 2)

(ME-6950)

A feature-rich dynamics cart for virtually friction-free motion on a dynamics track.

PAStrack

(ME-6960)

Connect two 0.5m length tracks and use with PAScars to study motion.

Track Rod Clamp

(ME-9836)

Fastens to the T-Slot of a Dynamics track and accepts a 1/2 inch rod.

Cart Picket Fences (2 Pack) -- IDS

(ME-9804)

Replacement photogate fences that mount on Dynamics Carts.

Angle Indicator

(ME-9495A)

Fastens to the T-Slot of a dynamics track with hanging brass plumb bob for angle indicator.

Dynamics Track End Stop (2 Pack)

(ME-8971)

Replacement end stops for the Dynamics Tracks.

Aluminum Table Clamp

(ME-8995)

This clamp with 6.5 cm grip width, accepts plain or threaded rods up to 1/2 inch or 1.25 cm.

45 cm Stainless Steel Rod

(ME-8736)

Non-threaded and non-magnetic lab rod.

Four Scale Meter Stick

(SE-8695)

A convenient measuring device that includes four different metric scales of various precision.

Ohaus Scout SKX Balance 2000g

(SE-8757B)

Combines range, resolution and low cost, making it ideal for the student science lab. 2000 g version.

Materials Used:

The Ohaus Scout Pro Balance 2000g listed in the Materials and Equipment section is for classroom use, not individual lab stations.

The Associated Bundle:

Advanced Physics 1 Starter Bundle

(PS-2815)

Equipment and sensor starter bundle for performing 8 experiments in the Advanced Physics through Inquiry 1 Teacher Guide.

Interface Required

This experiment may require software and an interface for data collection.