Vertical Projectile Launcher, 1C20.60

Topic and Concept:

• Motion in One Dimension, 1F20. Uniform Acceleration

Location:

• Cabinet: Mechanic (ME)

• Bay: (A5)

• Shelf: #1

  

Abstract:

Using the Pasco projectile launcher, a projectile is launched vertically from a risen platform relative to the ground. The projectile will reach a maximum height, stop, then fall to the ground reaching its greatest speed just before impact.

Important Setup Notes:

• N/A

Setup and Procedure:

1. Position the Pasco launcher on the table, and adjust the angle so that it is oriented vertically relative to the floor.
2. Load the launcher by placing a Pasco projectile in the launcher, and push it down with the loading rod until the

Cautions, Warnings, or Safety Concerns:

• DO NOT look down the barrel of the projectile launcher - a spontaneous launch could take your eye!
• Take care to not aim the projectile launcher at or near the audience; also keep in mind the possible post-contact trajectories of the projectile.

Discussion:

The only force on the projectile after it leaves the launcher is gravity. It is given an initial velocity by the launcher. The position of the projectile as a function of time is given by the position equation y(t)=(1/2)*g*t²+v₀*t where y is the vertical displacement relative to the launcher muzzle, t is the time elapsed since launch, g is the acceleration due to gravity 9.81 m/s² and v₀ is the initial velocity of the ball. A rough estimate of the muzzle velocity can be obtained by measuring the spring constant of the launching spring inside the launcher. Also, the mass of the projectile, the compressed length of the spring at each of the three strength settings, and the uncompressed length of the spring would need to be measured. Hooke's Law can then be applied to obtain the kinetic energy imparted to the projectile and therefore its initial velocity.

Videos:

• Lecture Demonstration's Youtube Channel

References:

• N/A

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