Posted: January 30th, 2015

Suppose your hair grows at the rate 1/33in. per day. Find the rate at which it grows in nanometers per second. Because the distance between atoms in a molecule is on the order of 0.1 nm, your answer suggests how rapidly layers of atoms are assembled in this protein synthesi

1. Suppose your hair grows at the rate 1/33in. per day. Find the rate at which it grows in nanometers per second. Because the distance between atoms in a molecule is on the order of 0.1 nm, your answer suggests how rapidly layers of atoms are assembled in this protein synthesis.
   Answer: ___nm/s

2. A large man sits on a four-legged chair with his feet off the floor. The combined mass of the man and chair is 95.0 kg. If the chair legs are circular and have a radius of 0.400cm at the bottom, what pressure does each leg exert on the floor?
   Answer: ___Pa

3. The spring of the pressure gauge shown in the figure below has a force constant of 1 150N/m, and the piston has a diameter of 1.40cm. As the gauge is lowered into water in a lake, what change in depth causes the piston to move in by 0.440 cm?
   Answer: _____m

4. What must be the contact area between a suction cup (completely evacuated) and a ceiling if the cup is to support the weight of an 92.4-kg student?
   Answer: _____m²

5. (a) Calculate the absolute pressure at the bottom of a freshwater lake at a point whose depth is 32.7m. Assume the density of the water is 1.00 10³ kg/m³ and the air above is at a pressure of 101.3 kPa.
   Answer: _____Pa(b) What force is exerted by the water on the window of an underwater vehicle at this depth if the window is circular and has a diameter of 28.6 cm?
   Answer: ______ N

6. A container is filled to a depth of 18.0cm with water. On top of the water floats a 30.0-cm-thick layer of oil with specific gravity 0.900. What is the absolute pressure at the bottom of the container?
   Answer: ______Pa

7. Mercury is poured into a U-tube as shown in Figure a. The left arm of the tube has cross-sectional area A₁of 10.8cm², and the right arm has a cross-sectional area A₂ of 5.90 cm². Four hundred grams of water are then poured into the right arm as shown in Figure b.

(a) Determine the length of the water column in the right arm of the U-tube.
Answer: _____cm

(b) Given that the density of mercury is 13.6 g/cm³, what distance h does the mercury rise in the left arm?
Answer: ______cm

8. Estimate the total mass of the Earth’s atmosphere? (The radius of the Earth is 6.37 10⁶m, and atmospheric pressure at the surface is1.01  10⁵ N/m².)

Answer: ______kg

9. A submarine is at a depth of 12.0m under the ocean surface. The inside of the submarine is kept at atmospheric pressure. What is the net force being exerted on a circular window of the submarine that has a radius of 45cm? The density of the ocean water is 1030 kg/m³.