The potential energy of the block is A) 490 J
Explanation:
The potential energy of an object is the energy possessed by the object due to its position in the gravitational field.
It is calculated as follows:

where
m is the mass of the object
g is the acceleration due to gravity
h is the height of the object above the ground
For the block in this problem, we have:
m = 10 kg

h = 5 m
Therefore, its potential energy is:

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Answer: True
Explanation: Following are the properties that are used to identify minerals:
(1) Color
(2) Hardness
(3) Magnetism : It is the property of mineral to attract or repel with other magnetic materials.
(4) Luster : It is the property that shows the surface is reflecting light or not.
(5) Reactivity: Reactivity is also responsible to identify mineral. How the mineral is reacting with acids, bases etc helps to identify type of minerals.
The answer to your question is true.
Answer:
<u>For M84:</u>
M = 590.7 * 10³⁶ kg
<u>For M87:</u>
M = 2307.46 * 10³⁶ kg
Explanation:
1 parsec, pc = 3.08 * 10¹⁶ m
The equation of the orbit speed can be used to calculate the doppler velocity:

making m the subject of the formula in the equation above to calculate the mass of the black hole:
.............(1)
<u>For M84:</u>
r = 8 pc = 8 * 3.08 * 10¹⁶
r = 24.64 * 10¹⁶ m
v = 400 km/s = 4 * 10⁵ m/s
G = 6.674 * 10⁻¹¹ m³/kgs²
Substituting these values into equation (1)

M = 590.7 * 10³⁶ kg
<u>For M87:</u>
r = 20 pc = 20 * 3.08 * 10¹⁶
r = 61.6* 10¹⁶ m
v = 500 km/s = 5 * 10⁵ m/s
G = 6.674 * 10⁻¹¹ m³/kgs²
Substituting these values into equation (1)

M = 2307.46 * 10³⁶ kg
The mass of the black hole in the galaxies is measured using the doppler shift.
The assumption made is that the intrinsic velocity dispersion is needed to match the line widths that are observed.