Answer:
The length of the rope must be an integral multiple of the wavelength of the wave.
Explanation:
-- 6 people all trying to push a car out of snow
-- a Tug-o-War with 30 people of different sizes pulling on each end of the rope
-- you and your sister both pulling on the same doll (or Transformer)
-- lifting a book up from the table to a high shelf
taking a book down from a high shelf to the table
(one force is you; another force is gravity)
-- grabbing your big dog by his collar and trying to bring him inside
-- three people at the table all grab the ketchup bottle at the same time
Answer:

Explanation:
Power is related to energy by the following relationship:

where
P is the power used
E is the energy used
t is the time elapsed
In this problem, we know that
- the power of the fan is P = 120 W
- the fan has been running for one hour, which corresponds to a time of

So we can re-arrange the previous equation to find E, the energy (in the form of thermal energy) released by the fan:

Answer:
its the sound that a heart produces when beating, this can help doctors detect abnormalities