physics of figure skatingjackiemeans.weebly.com/.../jfigure_skating.pdf · when it is a figure...

Physics of Figure Skating

Jackie Means

Motion/Position/Time

• Once the skater is in motion, they

remain in motion until their whole

routine is finished. Whether they’re

gliding, jumping, or just skating in a

straight line.

• To gain speed, the skater will skate

along the outer edges of the rink,

gaining speed into their next move.

Velocity & Acceleration

A skater can change their velocity

by applying more force onto one of

their legs, going into the direction

they wants to go in.

They accelerate by

applying a greater force

onto the ice.

•Velocity: the rate and direction of change in the position of an object

•Acceleration: An increase in rate of change: speed/velocity

If a skater accelerated from

0 m/s to 2 m/s in 5 seconds,

then her acceleration is .4 m/s^2

Vavg=Displacement

Time

Aavg=Final Velocity - Initial velocity

Final Time - Initial Time

If a skater skated 7 m

within the first 15 sec of

her routine, her average

velocity was .5 m/s

Newton’s Laws

“For every action, there is an

equal & opposite reaction”

This allows the skater to move

across the ice. When they push off

against the ice, they apply a

downward force on the ice. In

return, the ground pushes right

back with an upward & forward

force, propelling the skater

forward, or up into a jump,

depending on the particular force

they applied.

QuickTime™ and a

TIFF (Uncompressed) decompressorare needed to see this picture.

“An object in motion

tends to stay in motion,

unless acted upon by an

outside force”

It is also known as inertia,

and it’s why the skater,

whose motion isn't being

acted on by a force of

friction powerful enough to

stop them, tend to stay in

motion unless they use force

to stop themselves.

“The greater the mass of the

object, the greater the force

it takes to accelerate it”

F=ma

As the skater goes into a low

spin, they apply more and

more force to the ice as they

get lower and lower, this

results in an acceleration and

a faster spin.

Ex: The skater is 50 kg and is

accelerating at 1.2 m/s. their

force would be 60 N

Work

• The amount of force it takes to move an object a certain distance.

• W=F*d*cos

• The skater’s force is 60 N they jump at a 24 degree angle, going 5 m. How much work is being done?

60 x 5 x cos 24= 274.1 J

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Work (continued)

When it is a figure skater pair, the jumps and routine become

a lot more complicated. You have to factor in that extra

person and combine two people’s routines into one.

Generally, while skating as a pair, instead of just jumps and

turns, lifts are incorporated. Work is being demonstrated as

the skater lifts his partner up into the air.

As he lifts her 2.1 m into the air, it takes a force of 535 N,

How much work is being done?

2.1m x 535 N = 1123.5 J QuickTime™ and aTIFF (Uncompressed) decompressor


Gravity

• Gravity immediately starts slowing the skater's vertical velocity when he leaves the ice, but

since it’s acting only in the in the vertical direction, it has no affect on the skater’s horizontal

motion. only an external force acting in the horizontal direction, (air resistance) would affect

the skater's horizontal velocity. Once gravity has slowed the skater's upward vertical velocity

to zero, gravity then pulls the skater back to down to the ground, ending the jump.

• Gravity is also what keeps the ice skater secured to the ground. The ice has friction, but not

as much as other surfaces, like concrete or dirt. But as with any surface, without the

downward pull of gravity, the skater wouldn’t be able to keep themselves on the ground, or

even be able to stop themselves.



Potential & Kinetic Energy

• In a jump, the skater uses chemical potential energy

(muscle power) to gain speed across the ice. when she

jumps, she converts that chemical potential energy into

kinetic energy. As she flies upward, her kinetic energy

turns into gravitational potential energy. Then at the top of

her jump, for just a moment she has no kinetic energy at

all. There,the kinetic energy changes into gravitational

potential energy. Then, as gravity pulls her back down, her

potential energy is converted back into kinetic energy.

When she hits the ice, all the gravitational potential energy

she had at the jump's peak is changed once again into

kinetic energy and she comes back down hitting the ice

pretty hard. By measuring the height of her total jump, you

can determine how hard she pushed off, which is also how

hard she came down.





Potential & Kinetic Energy (Continued)

PEgrav=m*g*h

m= mass (kg)

g= pull of gravity (9.81m/s ^2)

h= height (m)

KE= 0.5*m*v^2

m=mass (kg)

v^2= velocity (m/s) squared

A 50 kg skater makes a

jump, going the height of

3.4 m at the peak of the

jump, before gravity pulls

her back to the ground.

What is her gravitational

potential energy?

50 kg x 9.81 x 3.4 m= 1667.7J

That same 50 kg skater has

a velocity of 2.3 m/s. What

is her kinetic energy?

0.5 x 50 kg x 2.3 ^2= 132.25 J

Waves

Mechanical Wave: Sound

As the skaters skate, they

choreograph their routines to a

certain song or musical

arrangement, thus producing

sound waves Electromagnetic Wave: Visible

Without visible light, we wouldn’t be

able to see the colors of the skater’s

intricate leotards

ex: If they’re wearing a red leotard, all

of the light besides the red is being

absorbed, while the red is being

reflected, giving us the color that our

eyes familiarize as red







Waves Comparison:

Visible Sound

Frequency 4 - 7.5X10^14 Hz 20 Hz - 20 kHz

Wavelength 750 - 400 nm 17-.017m

Wave speed 3.0 x 10^8 m/s 340 m/s

Period .25- 1.3334 x 10^-15

sec .05- 5 x 10^-5 sec

=c/f

= wavelength

c=speed of sound

f=frequency

As for the electromagnetic spectrum, Visible is fourth on the spectrum,

but sound isn’t on the spectrum at all.

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