Answer
I am not sure but it is may be 50J
I hope that's, this answer is fine.
Answer:
Car first should be 30.13 m behind the second car.
Explanation:
Given that,
Constant speed = 108.5 Km/hr
Time = 1 sec
Let the distance covered by second car S and by first car S'
We need to calculate the distance covered by second car
Using equation of motion
.....(I)
The distance covered by first car to avoid collision

Put the value into the formula
...(II)
We need to calculate the distance covered by first car
Using equation (I) and (II)

Put the value into the formula


Hence, Car first should be 30.13 m behind the second car.
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Answer:
D. They have the same number of valence electrons
Explanation:
In order to answer this question we need to understand the following.
- Valence electrons refers to the outermost electron(s) in the outermost energy level of an atom.
- Elements in the same group in the periodic table have the same number of valence electrons. For instance, group 2A elements have 2 valence electrons.
- The reactivity of elements in the periodic table is based on the number of valence electrons and the ease of gaining or losing electrons.
- Elements in the same group have similar valence electrons and therefore share similar chemical properties such as reactivity.
- Hence, elements in the same group have same number of valence electron and will thus have similar reactivity.