Molecular Physics | Thermodynamics Answers

A 4.2 x 10^3 kg car accelerates from rest at the top of a driveway that is sloped at an angle of 18.4 degrees with the horizontal. An average frictional force of 4.1 x 10^3 N impedes the car's motion so that the car's speed at the bottom of the driveway is 4.9 m/s.
the acceleration of gravity is 9.81 m/s^2 . What is the length of the driveway?

work done in bringing a mass from infinity to center of earth

If you found yourself on perfectly smooth ice in the center of a pond so that there was no friction, how could you get of the pond?

Blood flows through a section of a horizontal artery that is partially blocked by a deposit along the artery wall. As a hemoglobin molecule moves from the narrow region into the wider region, its speed changes from v2 = 0.800 m/s to v1 = 0.442 m/s. What is the change in pressure, P1 - P2, that it experiences? The density of blood is 1060 kg/m3.

http://edugen.wileyplus.com/edugen/courses/crs3976/art/qb/qu/c11/c11_q_17.gif

A glass tube has several different cross-sectional areas with the values indicated in the figure. A piston at the left end of the tube exerts pressure so that mercury within the tube flows from the right end with a speed of 8.0 m/s. Three points within the tube are labeled A, B, and C.
http://edugen.wileyplus.com/edugen/courses/crs3976/art/qb/qu/c11/r5-1.png

Notes: The drawing is not drawn to scale.
Atmospheric pressure is 1.01 × 105 N/m2; and the density of mercury is 13 600 kg/m3.

What is the total pressure at point B?

A balloon is released from a tall building. The total mass of the balloon including the enclosed gas is 2.0 kg. Its volume is 5.0 m3. The density of air is 1.3 kg/m3.

Will the balloon rise, fall, or remain stationary; and why?




The balloon will fall because the downward buoyant force is greater than the upward buoyant force.



The balloon will fall because the upward buoyant force is less than its weight.



The balloon will fall because its density is greater than that of air.



The balloon will remain stationary because its density is less than that of air.



The balloon will rise because the upward buoyant force is greater than its weight.

A water line with an internal radius of 5.29 x 10-3 m is connected to a shower head that has 13 holes. The speed of the water in the line is 2.69 m/s. (a) What is the volume flow rate in the line? (b) At what speed does the water leave one of the holes (effective hole radius = 5.87 x 10-4 m) in the head?

Blood flows through a section of a horizontal artery that is partially blocked by a deposit along the artery wall. As a hemoglobin molecule moves from the narrow region into the wider region, its speed changes from v2 = 0.800 m/s to v1 = 0.411 m/s. What is the change in pressure, P1 - P2, that it experiences? The density of blood is 1060 kg/m3.

In a classroom demonstration, a 79.2-kg physics professor lies on a "bed of nails." The bed consists of a large number of evenly spaced, relatively sharp nails mounted in a board so that the points extend vertically outward from the board. While the professor is lying down, approximately 1950 nails make contact with his body.

If the area of contact at the head of each nail is 1.26 × 10 –6 m2, what is the average pressure at each contact?

A water line with an internal radius of 5.70 x 10-3 m is connected to a shower head that has 13 holes. The speed of the water in the line is 1.27 m/s. (a) What is the volume flow rate in the line? (b) At what speed does the water leave one of the holes (effective hole radius = 3.92 x 10-4 m) in the head?