Water circulates in a thermosiphon, hot water system because ...

[pragya sharda]

Water circulates in a thermosiphon, hot water system because ________.
 a. a pump is used
  b. gravity causes water to flow from the top of the collector to the bottom
  c. hot water is less dense than cold water
  d. solar energy is used to run the circulating pump

Question 2

A uniform ladder 15 ft long is leaning against a frictionless wall at an angle of 53 above the horizontal. The weight of the ladder is 30 pounds. A 75-lb boy climbs 6.0-ft up the ladder. What is the magnitude of the friction force exerted on the ladder by the floor?
 a. 43 lb
  b. 34 lb
  c. 38 lb
  d. 47 lb
  e. 24 lb

[Hdosisshsbshs]

Answer to Question 1

c

Answer to Question 2

B

[pragya sharda]

Thanks for the timely response, appreciate it

[ashely1112]

Wow, this really help