Answer:
<h2>392 J</h2>
Explanation:
The potential energy of a body can be found by using the formula
PE = mgh
where
m is the mass
h is the height
g is the acceleration due to gravity which is 9.8 m/s²
From the question we have
PE = 20 × 9.8 × 2
We have the final answer as
<h3>392 J</h3>
Hope this helps you
D- All wave lengths refract at the same angle
Explanation- The amount of refraction increases as the wavelength of light decreases. Shorter wavelengths of light are slowed more and consequently experience more bending than the longer wavelengths.
The properties of acids are: (A), (C) and (D).
Explanation:
Acids taste sour, and most
acids are poisonous. Furthermore, acids react with certain metals to
produce hydrogen gas. Few acids are corrosive as well. The option (B) is not valid because acids react with BASES (not with other acids) to produce salt and water. Hence A, C and D are the correct options.
Answer:
The maximum height a person's brain could be above his heart is: 1.28 meter.
Explanation:
We need to know what is the normal blood pressure ours hearts so there is a rate: 120/80 (mmHg) and the average will be: 100 (mmHg) and using the Pascal law that relate pressure, density, gravity and height like:
, where P is pressure, p is density, g is the gravity acceleration and h is the height. Now we can find the height and delta of pressure will be: P2-P1 = 100 (mmHg), knowing that 1(mmHg) is equal to 133 Pa, we can do the convertion to 13332.2 (Pa), now because the units of Pascal are Newton/(meter^2). Then we solve the formula to get the height:
so we get: