The approximate answer is 6.84. Reasoning: (2.78^2 + 6.25^2)^(1/2) = 6.84 approx.
Answer:
Statements 4, 6 & 7 are incorrect.
Explanation:
In any elastic collision, the overall momentum vector sum of the system remains zero.
In this scenario, an elastic collision occurs between the ball and a stationary wall. The ball's velocity will consistently revert after the impact, leading to a change in direction of momentum.
The initial momentum of the ball is represented as:

where:
m = mass of the ball
v = initial velocity of the body
post-collision for the elastic interaction:

- Here, the momentum changes solely in direction, thus contradicting statement 7.
- During the impact, both the ball and the wall exert forces on each other that are equal and opposite. The wall remains motionless, while the ball is influenced by the wall's reaction force, performing work on it, which contradicts statement 4.
- Given that this collision is elastic, the ball's form and dimensions do not alter.
- The previous points clearly indicate that not all provided statements hold true, thus violating statement 6.
<span>Response:
Chlorine has 17 electrons, thus, for 1+ and 2+ ions, we require elements with 18 and 19 electrons, which are argon and potassium: Ar+ and K 2+.
For 1- and 2- ions, we need elements with 16 and 15 electrons, namely sulfur and phosphorus, represented as S- and P 2-.
It’s important to note that + ions indicate electron loss, while - ions reflect electron gain.</span>