Advanced Physics Through Inquiry 1 Teacher Guide

(PS-2848)

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

Rotational Statics

Lab Summary

Students use a force sensor and tension protractor to demonstrate that the sum of the forces acting on an object in static translational equilibrium is equal to zero, and the sum of the torques acting on an object in static rotational equilibrium is equal to zero.

Theory

What must the net force and net torque on an object be if the object is in static equilibrium (translational and rotational)? Experimentally demonstrate that the sum of the forces acting on an object in static translational equilibrium is equal to zero, and the sum of the torques acting on an object in static rotational equilibrium is equal to zero.

Method

The Structured version of this lab activity is divided into two parts: Part 1 – Students suspend a 500-g mass from two lengths of thread and use two PASCO Tension Protractors to measure the tension and angle applied to the mass by each thread. Students then calculate the component forces acting on the mass as it hangs motionlessly, and sum each set of component forces. This process is repeated for two additional trials; each trial with a different thread length configuration. Student data for each trial will demonstrate that the sums of the component forces acting on the mass in static equilibrium are equal to zero (or nearly zero) for both the x- and y-directions. Part 2 – Students balance a meter stick on a fulcrum (directly under its center), and then place a 100-g mass at different distances from the fulcrum (pivot point) while applying a force, using a force sensor, to the meter stick on the opposite side of the pivot. When the applied force is enough to balance the meter stick and mass (static equilibrium), students record the force applied by the force sensor, the distance from the pivot to the force sensor, and the distance from the pivot to the mass. Students then calculate the torques applied to the meter stick by the mass and the force sensor and demonstrate that when the meter stick is in static equilibrium, the sum of the torques is zero, regardless of where the mass and force sensor are positioned.

Sensors / Equipment Used:

PASPORT High Resolution Force Sensor

(PS-2189)

Designed to measure both pulling and pushing forces. Provides a very high resolution of data collection.

Tension Protractor

(ME-6855)

A spring scale and a protractor integrated into one device. Perfect for vector analysis of forces.

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.

90 cm Stainless Steel Rod

(ME-8738)

Non-threaded and non-magnetic lab rod.

Stainless Steel Rod, 60 cm Threaded

(ME-8977)

Threaded stainless steel rod with diameter of 1/2 inch.

Right Angle Clamp

(SE-9444)

This clamp fits rods up to 18 mm (11/16 in) in diameter.

Hooked Mass Set

(SE-8759)

A rugged cast-iron mass set that is coated with enamel.

Four Scale Meter Stick

(SE-8695)

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

Black Thread (3 pack)

(ME-9875)

Black nylon thread.

Materials Used:

Tape
AA-cell Battery or similar cylindrical object
Scissors

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.