That they travel in a vacuum. All other waves require a medium in which they wave.
GIVEN:
60 beats per minute
21 beats per minute
find x= how fast would an astronaut be flying away
1 x
----- * ------ = (60x = 21) -------> 60x = 21 ------------> x= 0.35
60 21 ------- -----
60 60
The answer is 0.35 seconds which refers to how fast would an astronaut be flying away from the earth if he has a heart rate of 21 beats/min.
Answer:
The work done by gravity is 
Explanation:
The data given in the question is :
Mass is 
Height from ground is 
As we know , the work done is state function , it depends on initial and final position not on the path followed.
So, work done by gravity = change in potential energy
Work done = Initial potential energy - final potential energy
Insert values from question
Work done = 
Work done = 
So, work done = 
Hence the work done by gravity is 
Answer:
4.4721m
Explanation:
#Use Pythagorean theorem to find the distance between the two speakers:

There are antinodes 1/4,1/2 and 3/4 of the distance between speakers.
The greatest antinode is 3/4-1/4=1/2
#Distance between consecutive antinodes is:

Hence, the maximum possible wavelength of the sound waves is 4.4721m
Electrical power is defined as
P = I * V
I = 3 amperes
V = 240 volts
Power = 3 * 240
Power = 720 Watts. Answer