Answer:
He is wrong!
Explanation:
Frequency refers to how many wave lengths pass in a second and speed is how fast the wave is traveling for example the speed of light goes really fast but has a mid-level frequency.
Hope this helps! ;-)
Answer:
The sound intensity is still the same. The sound intensity level does not depend on the number of sound sources but only the wave properties of the wave medium and the properties of the sound source. The wave properties of the medium includes the density and also the temperature.
Explanation:
Currently, there are no black dwarfs that exist in our universe. Black dwarfs are extremely cool and are almost invisible. They are hypothetical in existence.
Answer:
<em>D. The acceleration after it leaves the hand is 10 m/s/s downwards
</em>
Explanation:
<u>Vertical Throw
</u>
When an object is thrown upwards, it describes a special type of motion ruled only by gravity.
When the ball is launched, it has its maximum speed upwards. The acceleration of gravity is always the same because it's a constant value near our planet's surface. The object starts to lose speed since the acceleration of gravity is pointed downwards and makes the object stop in the mid-air at its maximum height, where the speed is zero. Then, the object starts to fall and regain speed, this time downwards until it reaches back the launching point at the very same speed it was launched, but in the opposite direction.
The time it takes to reach its maximum height is the same it takes to return to the catching point, 2 seconds later.
With all these concepts in mind, we state that:
<em>D. The acceleration after it leaves the hand is 10 m/s/s downwards </em>
The other options are not correct because:
A. The acceleration is never upwards
B. The acceleration is never 0
C. Both times are equal
Answer:
141
Explanation:
The atomic number (Z) corresponds to the number of protons:
Z = p
while the mass number (A) corresponds to the number of protons+neutrons:
A = p + n
So the number of neutrons in a nucleus is equal to the difference between mass number and atomic number:
n = A - Z
For the initial nucleus of Uranium, Z = 92 and A = 235, so the initial number of neutrons is
n = 235 - 92 = 143
An alpha particle carries 2 protons and 2 neutrons: so, when the isotope of Uranium emits an alpha particle, it loses 2 neutrons. Therefore, the number of neutrons after the decay will be
n = 143 - 2 = 141
