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Quiz #2 - Winter Sports
| 1.
What part of a skater's body helps her spin so quickly
in the air and on the ice? |
| a)
Feet |
| b)
Arms |
| c)
Head |
| d)
Legs |
Answer is B: Spinning objects, such as skaters, have angular
momentum which is a property that describes the mass, radius,
and speed of a spinning object. Since a skater's mass stays
the same whether she is spinning or standing still, the other
two components take over to balance each other out. If the radius
gets bigger, the rate of speed gets smaller and vice versa.
So, if a skater stretches out her arms, she is increasing her
body's radius which will decrease her speed. If she pulls her
arms in tight to her chest however, she will decrease her radius
and increase her speed. |
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| 2.
Why are hockey pucks frozen before each game? |
| a)
So they won't melt the ice |
| b)
So they will be the same temperature as the ice |
| c)
So they will be darker |
| d)
So they will be harder |
Answer is D: Pucks are made of rubber. Room temperature rubber
is soft and it molds to the things around it so an unfrozen
puck would bend around a hockey stick. It would also grip the
ice, creating friction, instead of sliding smoothly across the
surface. Frozen pucks are harder so they stay stiff when hit
and they slide smoothly across the ice. |
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| 3.
How does the wax that cross country skiers put on the
bottom of their skis help? |
| a)
It makes the skis slipperier |
| b)
It makes the skis stickier |
| c)
It makes the skis warmer |
| d)
It makes the skis colder |
Answer is B: Most people think skiers use wax to make the bottom
of the ski slipperier but they actually use the wax for the
exact opposite reason. In cross country skiing, the skier needs
to have the ski grip the snow just a bit in order to be able
to push off for the next glide. Without wax, skis would just
slip on the snow and the skier wouldn't be able to get a good
push. The wax sticks to the snow just enough to hold it in place
so that the skier can get a good push. |
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| 4.
Which two scientific principles do bobsledders use to
help them win? |
| a)
Acceleration and aerodynamics |
| b)
Pressure and thermodynamics |
| c)
Elastic energy and potential energy |
| d)
Angular momentum and torque |
Answer is A: The sled needs to start with as much acceleration
as possible because the force of the track on the sled will
create friction which slows it down. So, the racers need to
sprint as fast as they can at the start of the race in order
to get the fastest starting speed possible. Once they have all
hopped in the sled, aerodynamics come into play. As air rushes
past the sled, it collides with the sled and the riders, slowing
everything down. If they are sitting upright, they will bump
into more air molecules, causing them to slow down a great deal.
By ducking into the sled, they reduce the amount of molecules
they hit which helps them move faster. |
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| 5.
What word best describes a skate blade? |
| a)
Aerodynamic |
| b)
Elastic |
| c)
Convex |
| d)
Concave |
Answer is D: Blades on both hockey and figure skates are concave
which means that there is a hollow area carved into the blade,
running down the center, from front to back. As a result of
this hollow, blades have two edges - the inside edge which is
toward the big toe, and the outside edge which is toward the
pinky toe. Blades have this shape because skaters know their
physics. They know that being able to switch from an edge (when
they lean to one side) to the flat of their skate (when they
skate with the whole blade touching the ice) allows them to
control friction. When skaters dig their edges into the ice,
they create friction which slows them down - very handy when
they need to make a quick stop or change direction. When skaters
switch to a flat there is less friction, making it easier to
glide in a straight line. |
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