Shoot-n-Drop
acceleration due to gravity - projectile motion - velocity components
What it shows:
The horizontal and vertical motions of a projectile are independent of each other. So two
objects falling under the influence of gravity from the same height will reach the ground
simultaneously, regardless of their horizontal velocities.
How it works:
The device, built by Welch,
1
consists of a spring loaded rod that shoots one of two small wooden balls horizontally (pin-ball
machine fashion). The second ball has a hole through it so that it slips over the other end of the
rod. As the rod is released to fire ball #1, it slips out through ball #2 which then falls to the ground.
figure 1.
Setting it up:
The Welch device clamps to a bench but protrudes over the edge giving the balls freedom of
movement. A hard floor is vital here, because the best way to judge whether the balls strike
the ground simultaneously is to listen for one or two cracks as the wooden balls land.
Comments:
Although the sound of the balls is audible to an entire hall, the device itself is too small for such
an arena. A larger version (say using bowling balls) would be a good future project. Rating **
1 Welch Scientific, Chicago Ill., now Sergent-Welch. The Shoot-n-Drop is no longer made.