The Physics of Ski Jump

1. “Brown Out” Classroom Module Program K-12 Educational Outreach CONTACT: http://www.brown.edu/CAMR OUTREACH Brown University Center for Advanced Materials Research The Physics of Ski Jump Jorge Viamontes Brown University Designed by: Prof. Janet Blume Division of Engineering Brown University Ms. Rebecca Cituk Portsmoth Middle School

2. What is a ski jump? http://www.huikuri.com/games/skijump/

3. What Do Ski Jumps have to do with Math & Science??? • Gravity • Drag • Friction • Launch Angle

4. GRAVITY "Gravity is the force that pulls you down." • Gravity is one of the universal forces of nature. It is an attractive force between all matter, and is very weak as compared to the other forces of nature. The gravitational force between two objects is dependent on their masses, which is why we can only see gravity in action when at least one of the objects is very large (like the Earth). • Isaac Newton was the first scientist to define gravity mathematically when he formulated his law of universal gravitation. The law of gravitation says that gravity is strongest between two very massive objects, and gets much weaker as these objects get further apart. Gravity

5. Drag DragDrag is an aerodynamic force that resists the motion of an object moving through a fluid (air and water are both fluids). If you stick your hand out of a car window while moving, you will experience a very simple demonstration of this effect. The amount of drag that your hand creates depends on a few factors, such as the size of your hand, the speed of the car and the density of the air. If you were to slow down, you would notice that the drag on your hand would decrease. http://travel.howstuffworks.com/airplane1.htm Drag

6. How can we reduce drag? We see another example of drag reduction when we watch downhill skiers in the Olympics. You'll notice that, whenever they get the chance, they will squeeze down into a tight crouch. By making themselves "smaller," they decrease the drag they create, which allows them to move faster down the hill. (http://travel.howstuffworks.com/airplane1.htm)

7. Friction Friction is the resistance met when one object moves over or rubs against the surface of another. The force of friction can start things moving, slow them down, or even stop them. Two things that affect the amount of friction generated are the roughness of the surface and the weight of the object. http://pd.l2l.org/success/lessons/Lesson11/ISCc4_L.HTM friction

8. Launch Angle 90 degrees What goes up must come down’ goes the old saying. When a skier goes off the edge of the ski jump there are various factors that determine how far away the skier will come down. The launch angle together with the launch speed determines the distance the skier can cover through the air. What is an angle? Angle between directions given in units of degrees

9. The Experiment

10. Computer Calculation Using the excel spread sheet below type in the measurements for Launch Point Y and the Launch Angle. Record the Land Point x results on the Olympic Score Sheet. *Note: The Land Point is called the Estimated Land Point on the score sheet.

11. Let’s make our own ski jump launch angle ramp Land point x

12. Lab sheet for each group launch angle: __________(degrees) computer calculated land point x:_____________ (meters) experimental land point x:_____________ (meters) Sources of error: 1. 2. 3.