Golf Shot

Challenge:  To design a device that will launch a golf ball over a barrier towards a target.

Parameters: The launch device must fit in a 30 cm cube before being triggered.  It must rest on the floor.  It can only use the energy of springs, elastics, or gravitational potential for its operation.  It must launch a golf ball-sized projectile at an angle more than 44° above horizontal.  It must clear an obstacle (tree) 1.52 m tall.  Goggles must be worn at all times.  You may not keep your project in the classroom between classes.

Scoring:  Your launcher will be scored on several parameters, some of which you want to maximize, and others you want to minimize:

Mass of Launcher score (M) which is calculated as Log10 of mass in grams

Distance past the obstacle (d) in meters

Symmetry of the parabola (S) as a ratio greater than one, comparing distances on either side of the wall.

Formula:  d / M S

Rank will be based on score, with highest score earning highest rank.

Physics:  The path of a dense projectile upon release is approximately a parabola.  The initial velocity and launch angle are mathematically related to the maximum height and horizontal displacement.  In fact, every aspect of the motion can be calculated at the grade 12 level.  This is because we can assume the horizontal motion exhibits constant velocity while the vertical motion exhibits constant acceleration due to gravity, and that those two components are independent of each other.

Extensions: You should be able to describe the velocity of the projectile at any moment in time, and be able to hit any target at any position, not just at floor level.

Help/Hints: Getting the best result will involve achieving a large initial velocity at a precise and repeatable angle, and knowledge of the path through the air. 

All moving parts should be as light as possible so that less energy is wasted as kinetic energy of your launcher.  A “striker” design is easier to make, but harder to aim.  A “cannon” design is harder to make, but easier to aim.  Budget lots of time to practice using your device to reduce the impact of human factors.

Quiz Topics: Two Dimensional Kinematics

Online Text: ch 2, ch 3