Tutor profile: Dmitriy B.
Subject: Physics (Newtonian Mechanics)
Two athletes are in a race to get a large heavy crate on the concrete across a finish line 20 feet away. The strength athlete decides to push the crate downwards and forward while the skinny endurance athlete decides to pull it upward and forward. The crate weighs 2,000 newtons and the coefficient of friction between the wooden crate and .62. Which athlete has to apply a larger force to get the box moving if they apply their force at an equal angle.
The strength athlete would need to apply a greater force because he is pushing down therefore adding a vertical vector to the normal force. A greater normal force would mean a greater force of friction he must over come, while the endurance athlete is doing the opposite.
Griffith, a doctor during WWI, tried to find a vaccine for pneumonia. While doing this, he accidentally discovered the Transforming Principle. After treating mice with heat killed S-cells and live R-cells, what would you expect to happen with the mice? What is the transforming principle?
You would expect the mice to get pneumonia because the dead S-cells would pass on their DNA to the R-cells, which originally were not able to cause pneumonia. Therefore, the transforming principle is DNA.
What is the effect of the patella when going from knee extension to knee flexion?
The patella will cause a moment that creates an anterior translation of the tibia during the first half of flexion, and a posterior translation of the tibia during the second half of flexion.
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