Practice Questions

  1. A 10 kg object is sitting on a table on Earth, and has 0.1m of its surface in contact with the table. What is the gravitational force of the object, and what is the stress that this object applies on the table?
  2. A drop of a fluid encounters a stress of 1000 Pa, and strains 0.5 in 5 seconds. What is the viscosity of the fluid? How much would the same fluid strain if the same stress was applied for 50 seconds?"
  3. A block of rock is 10 meters long, 100 meters wide and 10 meters thick, and has a density of 3000 kg/m3. What is the stress beneath the block (assume it is on Earth)?
  4. An object is originally 8 meters long, but only 7.6 meters after is compressed for 1 minute. What is the strain rate? If the stress is relieved but the object stays deformed, what kind of substance is it?
  5. A stress of 1000 Pa is applied to a liquid that is 1 meter long. The object is 1 m long after the stress is applied for 30 seconds. You then apply a stress of 10000 Pa, and the object deforms substantially. What kind of substance is this? Why didn’t it deform under 1000 Pa of stress?

 

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