Physics of balls
Adam Szalai
Jurisich Miklós High School
KŐSZEG
I love sport,
I like to play football,
And I also love sciences…
I love basketball,
The ball•Size, shape, mass, material, elasticity – all depending on the sport
•Soccer, basketball, volleyball, handball, football, baseball, la-cross, golf, table tennis, tennis, bowling, snooker etc.
What happens to the ball?
•Collision–Starting: energy is given to the ball
• With rackets, hands, foot, stick, cue …
–Collision is more or less elastic
–Conservation of momentum can be used during the collision (angles!)
Deformation• Can be observed in low-speed movies
• Can be observed in case of slow motion (bubbles)
• Volume is approximartely the same
• Smaller surface bigger surface
Motion of the ball
• Rolling on the surface–Slows down and stops b/c of friction
–(E.g. golf; bowling etc.)
–Depends on the friction
Motion in the air
•Theoretically: projectile. The path is parabola– Vertically: uniformly accelerates (g)– Horizontally: Uniform motion
•In practice: air resistance affects the path
Why does the path bend?
• Air „sticks” to the spinning objects
• As spinning body moves, the relative speed is different, pressure is different (Bernoulli law)
Speed – pressure2
2
1vpp o
p
Vrelp
Vrel
Magnus effect
• In sport - bent path of the balls
• In traffic - on a two-lane road two oppositely moving cars
• Helicopters
• Etc.
Be careful with it; take advantage of it, you might become
famous…
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