Untitled Document

Physics Demo Number: 115

Approximate

Run Time: 10 min

Ballistic Ball Catcher

Demo Description

A cart is given a modest horizontal push on a low friction track.

An attached vertical -firing ball launcher is activated when the cart passes a post attached to the track.

The ball undergoes a vertical excursion up to a point several cm above the moving cart and falls back into its launch tube.

Scientific Principles

Independence of vertical and horizontal motions of a projectile in a uniform gravitational field.

Equipment

Pasco Track
Cart
Ballistic Cart Accessory
Trigger Post

Equipment Location

Track lives on a wall bracket on left rear wall of prep room (opposite the [H] Columns).
Kit (115) on [H-4-5] contains the Cart, Ballistic Cart Accessory, and Trigger Post.

Instructions

The first picture shows the basic configuration of the components (track, ballistic cart accessory, cart, and trigger post).With this setup, one is able to show the process of a vertically fired ball going up and back down into its launch tube.

The ball motion will be a straight line motion in the frame of the moving cart. It will be seen as a parabola in the lab frame.

The second picture gives a closer view of the system.

If one turns the power switch to “on” and statically moves the photo gate to the point where the trigger rod fires the ball , then the ball should rise several centimeters up into the air and fall back into its launch tube for a clean capture.

One has the round knob at the top right in the second picture, and another knob on the accessory face to the right of this one (not seen here), to fine tune the static fire/capture properties of the system.

Once this fine tuning is accomplished, then modest horizontal initial speeds of the cart should result in dynamic fire/capture behavior of the ball by its launch tube.