Answer:
The galaxies outside of our own are moving away from us, and the ones that are farthest away are moving the fastest. This means that no matter what galaxy you happen to be in, all the other galaxies are moving away from you
Explanation:
Answer:
33.516 kJ
Explanation:
Potential energy is given by:
PE = mgh
Where m is the mass, g is acceleration due to gravity, and h is the height. In this case:
PE = 38kg x 9.8m/s^2 x 90m = 33516 kg m^2/s^2 = 33516 J = 33.516 kJ
Answer:
6.86 meters
Explanation:
Let the compression of the string be represented by x, and the height of projection of the toy rocket be represented by h.
So that;
x = 9 cm = 0.09 m
In its rest position (i.e before the launch), the spring has a stored potential energy which is given as;
PE = 
K
= x 830 x 
= 415 x 0.0081
= 3.3615
The potential energy in the string = 3.36 Joules
Also,
PE = mgh
where: m is the mass, g is the gravitational force and h the height.
m = 50 g = 0.05 kg, g = 9.8 m
Thus,
PE = 0.05 x 9.8 x h
3.3615 = 0.05 x 9.8 x h
3.3615 = 0.49h
⇒ h = 
= 6.8602
The height of the toy rocket would be 6.86 meters.
Answer:
Apply this to waves: count the number of waves passing each second (= frequency), and multiply by the length of each (= wavelength) to find the speed. speed = distance/time = l/T= l / (1/f) = f λ. Work through three examples: A simple example, perhaps for sound in air, with values in Hz and m.
Explanation:Apply this to waves: count the number of waves passing each second (= frequency), and multiply by the length of each (= wavelength) to find the speed. speed = distance/time = l/T= l / (1/f) = f λ. Work through three examples: A simple example, perhaps for sound in air, with values in Hz and m.
Amplitude is the fluctuation or displacement of a wave from its mean value. With sound waves, it is the extent to which air particles are displaced, and this amplitude of sound or sound amplitude is experienced as the loudness of sound
But it seems that in some circumstances, sound can jump between objects in a vacuum after all. Sound waves are travelling vibrations of particles in media such as air, water or metal. So it stands to reason that they cannot travel through empty space, where there are no atoms or molecules to vibrate.
