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Worksheet: Force and Pressure

Q1:

Why should you roll or belly-crawl rather than walk across a thinly-frozen pond?

  • AThe more of your body rests on the ice, the less you weigh.
  • BActually, you should walk on tip-toe so that your body heat does not melt the ice.
  • CIf you have more contact with the ice, the ice will warm up and expand, becoming more buoyant.
  • DThe greater your contact area with the ice, the lower the pressure and the risk of it breaking.

Q2:

Why are sharper knives more effective at cutting?

  • AThe smaller contact surface of a sharper knife can react faster with the surface of what is being cut.
  • BThe sharper the knife, the greater the torque on the cutting surface.
  • CSharper knives have smoother surfaces, allowing them to slide into the weak points of what is being cut.
  • DSharper knives have smaller contact areas so, with the same force, this translates to a greater pressure.