Vernier Motion Encoder System - Manual (Page 6)

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Wireless Dynamics Sensor System
For connection to a Vernier dynamics cart use a 5/8" × 10-24 binding barrel and a
hex-head bolt (1" × 10-24). First place the bolt head in the middle slot of the top of
the Vernier dynamics cart. Then lower the WDSS on top of the cart and insert the
binding barrel in the large hole of the WDSS. The bolt threads into the binding
barrel. Tighten the binding barrel. The process is shown in the series of photos
below:
General Hints for Vernier Motion Encoder System
 Do not install the magnets unless you know you want to use them. They will
interfere if you perform an experiment with a force sensor riding on the cart, since
the force sensor will then not read the total force acting on the cart.
 The magnets can be hard to pull apart if they stick together before installation;
slide them across one another to separate.
 The conventional arrangement for magnets is to have the cart ends attract the S
end of a compass needle. The key thing is that all magnets repel, so if you use the
opposite convention everywhere, no harm is done.
 The magnets are designed for fairly gentle collisions. If the cart is moving too
quickly, the magnetic forces may cause the cart to jump off the track to the side. If
this happens, use a lower initial velocity for the cart.
 Keep the track clean; if it is very dusty the carts will not roll smoothly.
 Use lower speeds and lower inclines than you might initially choose; the physics
is the same and students will have more time to observe what is happening.
 Attach the track feet, sliding at least one in about 30 cm before inserting the
Motion Detector Bracket.
 Study the Motion Detector Bracket photo carefully and note that the bracket is
attached to the underside of the track. A common error is to attach the bracket to
the top slot on the track.
 Some Dual Range Force Sensors come with a plastic bolt that is too long to allow
simultaneous attachment of the DFS with a MASS. If your bolt is long, use a wire
cutter to remove a few threads at a time.
Suggested Experiments with the Vernier Motion Encoder System
The Vernier Motion Encoder System can be used wherever a Motion Detector could
have been used with a cart and track. The encoder depends on the presence of the
track, so that only cart and track experiments can be performed.
Measure Cart Acceleration
The basic motion of a cart on a ramp can be studied. For example, perform
Experiment 3 from Physics with Vernier, “Cart on a Ramp.” Or, repeat Galileo’s
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experiment of determining g using an object and a ramp. This is Experiment 4,
“Determining g on an Incline,” from Physics with Vernier.
Newton’s Second Law
Use a force sensor on the encoder cart to record both applied force and acceleration.
The two will be proportional.
Or, set up a half-Atwood machine with a hanging mass and a pulley at the track end
opposite the receiver. Measure the acceleration of the encoder cart as a function of
the hanging mass.
Measure Fan Cart Acceleration
Add a Cart Fan (order code: FAN-VDS) to observe the motion of a cart under
constant thrust.
Measure Cart Acceleration with Friction
Add a Friction Pad (order code: PAD-VDS) to the encoder cart and observe the
motion of the cart with varying frictional forces.
Momentum-Impulse
Add a force sensor and a Bumper-Launcher Kit (order code: BLK) to observe the
relationship between momentum and impulse. Find the impulse by integrating under
a force vs. time graph.
Conservation of Energy
Use two Vernier Motion Encoder Systems to observe a change in energy due to a
collision between two carts.
Conservation of Momentum
Use two Vernier Motion Encoder Systems to observe a change in momentum due to
a collision between two carts. Try different kinds of collision: elastic, inelastic,
totally inelastic.
Products Related to the Vernier Motion Encoder System
Vernier Dynamics System (order code: VDS)
Vernier Dynamics System is a low-friction black anodized 1.2 m track and optics
bench combination designed for kinematics, dynamics, and optics experiments. It
includes two carts.
Vernier Dynamics System with Long Track (order code: VDS-LONG)
The long version of the Vernier Dynamics System includes a 2.2 m track instead of
the 1.2 standard track.
Track (order code: TRACK)
The Combination 1.2 m Track/Optics Bench comes with the Encoder System Strip
installed.
Bumper Launcher Kit (order code: BLK)
The Bumper Launcher kit includes accessories to integrate the Dual-Range Force
Sensor (DFS-BTA) with the Vernier Dynamics System or Vernier Motion Encoder
System, allowing for many interesting experiments in momentum-impulse study.