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1
2
Why it works
Weight is the pull of gravity on objects.
The weight of the coins adds to that of the
box.
Friction
resists the force of gravity,
but when there are more coins in the box
the force of gravity is greater than the force
of friction, so the box begins to move.
On the mountain, the extra weight of the
snowmobiles causes the avalanche.
Investigate weight and gravity. You need:
l
long piece of cardboard
l
empty box or carton
l
chair
l
weights, such as coins
Bend the cardboard so
there is a flat space at the
top, and a slope. Rest this
on a chair so the slope
reaches the ground.
Now put weights into
the box on the side that
is hanging over the
edge. Put one coin in at
a time. What happens?
Rest the empty box
or carton at the top of
the slope with an edge
hanging over, but so it
feels well balanced.
PROVE IT!
WHAT DO
YOU THINK?
Is Zac right, can extra weight
cause things to fall off a ledge?
