Reducing friction
3. Observe the design of water slides. How does it reduce friction to make people slide down more smoothly?
water
surface of a swimsuit
surface of a slide
with water as lubricant
without water as lubricant
Life Link Can we write with a pencil and leave our handwriting on these surfaces? Why or why not?
Water slides are made of materials with a smooth / rough surface. When water is used as lubricant, it further increases / reduces the friction between the surface of the water slide and the surface of the swimsuit, thus reducing the resistance.
paper
4. Does pulling an oil barrel upright or rolling it create smaller friction?
clear tape
1
2
Back to the Past When people needed to move stones in the past, they used logs as rollers to reduce friction.
pull an oil barrel upright
roll an oil barrel
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