To bring something to a stop the same force that was applied to speed it up can be used to stop it. If a greater force is used it will stop quicker.
The answer to the first one is sublimation.
Can you explain this a bit more I don’t quite understand
I think the correct answer from the choices would be that metals donate electrons to nonmetals. Ionic bonding involves transfer of valence electrons. The metal looses its valence electrons which makes it a cation while the nonmetal accepts these electrons.
Assume a maximum stopping acceleration of g/2 where g is acceleration due to gravity.
Answer:
2.99 m/s
Explanation:
Stopping distance, s = 3 ft = 0.914 m
final velocity, v = 0
a = g/2 = 4.9 m/s²
Use third equation of motion:

substitute the values to find the speed of train:
