21) Acceleration from D to E: 
22) The acceleration of the bus from D to E is 
Explanation:
21)
The acceleration of an object is equal to the rate of change of velocity of the object. Mathematically:

where
u is the initial velocity
v is the final velocity
t is the time elapsed
In this problem, we want to measure the acceleration of the bus from point D to point E. We have:
- Initial velocity at point D: u = 0
- Final velocity at point E: v = 5 m/s
- Time elapsed from D to E: t = 21 - 16 = 5 s
Therefore, the acceleration between D and E is

22) This question is the same as 21), so the result is the same.
Learn more about acceleration:
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Answer:
c
Explanation:
c. the ability to do work or to produce heat
Move from higher to lower energy levels
Answer:
(4) The physical and chemical properties of these minerals determine how humans use them.
Explanation:
All the materials and the metals found on earth shows certain characteristics naturally or in their physical state. These physical characteristics can be their look, their structure, their color, strength, melting point, boiling point, density, etc.
And chemical properties of the metals are defined as those characteristics or features of the metals that it exhibits when these metals reacts chemically.
The physical properties as well as the chemical properties distinguishes each metal from each other. These properties determines how people use these metals in their life.
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