Answer:
Pi(3.14) radians or 180º degrees
Explanation:
First of all, we need to obtain the wavelength of a wave traveling to the speed of sound and 420 Hz of frequency.
The formula is:

where l = wavelength in meters
With current values:
l = 336 [m/s]/420[1/s] = 0.8 meters
Since a complete cycle (360º or 2pi radians) needs 0.8 meters to complete, 0.4 meters or 40 cm is just half of it, making a 180º degree phase or 3.14 radians.
Answer:
8:P.E,9:gaining K.E,10:P.E,11:gaining K.E.
Explanation:
it gained potential energy at 8 because it was at its maximum height,and since potential energy is the energy that u posses due to ur height,thats the energy it possesed on the spot 8.as you can see on spot 9 its moving down so as its moving down,it gains kinetic energy,since its an energy possesed by a body due to its motion/movement,thats what it gained at spot 9, it gsained kineti energy because of its movement.and at 10 agian it would gain potential energy ecause of height and on point 11 as its heading upwards it gains kinetic energy because of movement.
Answer:
More than two million electron volts.
Explanation:
More than two million electron volts energy are needed to break or split a deuteron into a proton and a neutron. Nuclear binding energy is the type of energy that is required to split an atom's nucleus into protons and neutrons. The deuteron is an isotope of hydrogen that is composed of a proton and a neutron and it is a stable particle. Very huge amount of energy is needed for the splitting of nucleus due to the presence of heavy particles i.e. proton and neutron.