Michael Jackson The Physics of The Moonwalk Friction Torque Defying Physics Mg Fn2 Fn1 Ff2 Ff1 The Lean Friction: the force between two objects that opposes the direction of motion

Two types:

Static, μFn≥Ff

Kinetic, μFn=Ff Torque: a force that causes a rotation around a pivot point

The pivot is at Michael's toes

Forces acting on Jackson

Fg at his center of mass

Fn at the pivot point

At the lowest point of the lean, the torques around the toes must be equal for equilibrium

No force counters the mg, so MJ would fall mg Fn Torque Fn1 Fn2 Mg Ff1 Ff2 d1 d2 Calculations Angular Momentum Givens:

mass: 55kg

height: 1.8m

distance from toes to steel plate: 0.25m mg Fn Fshoes τ =F*d

Στ =0

Mgd1=Fn2d2 mg= 55 * 10 = 550N

Στ = 0

mg * d1 + Fshoes * d2 = 0

550 * 0.9 = Fshoes * 0.25

495 = Fshoes * 0.25

Fshoes = 1980N Fn1+Fn2=Mg

Ff1>Ff2 if Michael is to move backwards Angular momentum = mass * velocity * radius = mvr

Angular momentum is always conserved,so if the radius is decreased, the velocity must increase if mass stays constant

m1v1r1=m2v2r2 Friction So to increase the force of friction, the only way is to increase the normal force Mg=Fn1+Fn2 Mg=(Fn2*d2)/d1 (Fn2*d2)/d1-Fn1=Fn2 A downward force must be supplied on the heel to stop MJ from falling.

But how...? Magic Shoes MJ = "King of Pop

Known for his incredible dance moves

Applies knowledge of physics to move in ways that appear challenge what's possible d2 mg d1 Fn Angular Velocity is defined as the radians of a circle a particle travels per unit time

ω=d/r*t=v/r

ω=v/r

When Michael brings his arms in and grabs his belt, he spins faster due to a reduced radius Angular Velocity The Spin

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# Michael Jackson

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