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Physics

REMEMBER! DID YOU KNOW?

Independent variable: the variable you choose to
Frictional force results from two surfaces
change/vary.
touching each other, causing the
Dependent variable: the variable you will measure as intermolecular forces between molecules
a result of changing the independent variable. of the different surfaces to attract one another.
That means that friction depends on the types
textbooks nis edu kz
Constant (control) variable(s): the other variables in
of surface that are in contact with one another
your investigation that must remain constant so as not
and how close together they are. The higher
to affect the experiment.
the force acting on the surface, the higher the
What does friction force depend on? frictional force.

A skier skies down the mountain slopes after travelling Look carefully at the close-up of a gecko’s foot.
some distance. What resists the skier’s motion? A kinetic What do you notice? What has this got to do
friction force occurs during the motion of one object with frictional force?
across the surface of another, resisting motion. Surface
roughness is one of the reasons that friction occurs.

OVER TO YOU!

1. Explain and provide three different examples
of static, sliding and rolling friction that you
can find on your way to school.

2. What happens if you rub your hands
together for a minute? Repeat the
experiment after soaking your hands in
water. Compare the results. What happened?
3. Vehicles use different systems to brake and
slow down. Old vehicles used a ‘brake pad’
system and new vehicles use an Anti-lock
Braking System (ABS). Research the differences
between these two systems. Produce a leaflet
for your family to explain
how the two systems
work and what drivers
need to think about when
applying the brakes.

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