Compressed air is used to fire a 50 g ball vertically upward from a 1'0mtall tube' The air exerts an

1
Compressed air is used to fire a 50 g ball
vertically upward from a 1.0-m-tall tube. The air
exerts an upward force of 2.0 N on the ball as
long as it is in the tube. How high does the ball
go above the top of the tube?
2
Static Friction

• We can also consider ?S on an inclined plane.
• In this case, the force provided by friction will
  depend on the angle ? of the plane.

?
3
Static Friction

• The force provided by friction, fs , depends on ?.

a 0 (block is not moving)
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Static Friction

• We can find ?s by increasing the ramp angle until
  the block is just about to slide

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Additional comments on Friction

• Since f ?N, the force of friction does not
  depend on the area of the surfaces in contact.
• By definition, it must be true that
  for any system (think about it...).

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Aside

• Graph of Frictional force vs Applied force

f fs,max ?sN
f ?kN
f
f FAPPLIED
FA