Lab Notes: Week 5, Static and Dynamic Forces, Physics 3LB at UCI

Wk 5: Static and Dynamic Forces
Saturday, February 1, 2020 12:44 PM




• Goal is to measure forces of collisions using a force transducer, which converts forces to voltages


(read by DMM).


• NEWTON'S 2ND LAW: force must be applied to change a particle's momentum.


○ Forces are vectors-- have both magnitude and direction.


• Impulse: integral of the force over the collision time. Deltap = m(Vf - Vi)



• Elastic collisions: no energy is lost. Speed does not change, but direction does.


• Inelastic collision: energy is lost. Vi < Vf



• We will use force transducer made of strain gages. If force is applied to an insulator connected to the


wire (bonded to the gage), the insulator becomes strained and the resistance of the wire changes. -->


○ Voltage is proportional to the strain (only if a constant current is passed thru the wire)!


○ Gages arranged in an electrical configuration that allows output voltage to be proportional to the


applied force.


• PART ONE: DMM is used to measure this output voltage.


• PART TWO: PC mimicking a scope is used to measure this output voltage.


• Will be comparing voltage of an elastic and inelastic collision.