Answer:
Average acceleration on first part of the chunk is given as

Average acceleration on second part of the chunk is given as

Explanation:
By momentum conservation along x direction we will have

so we have


also by energy conservation






by solving above equation we will have


Average acceleration on first part of the chunk is given as


Average acceleration on second part of the chunk is given as


Answer with Explanation:
We are given that
Constant speed of Jane=12.6 m/s
a.When Fred can throw the ball 30 m/s
We have to find the angle relative to the horizontal when he throw the ball in order for Sue to see the ball travel vertically upward.
Let
be the angle .
Therefore,



b.We have to find the height to which ball reach.



B. five electrons
If you want an explanation, here it is.
The atomic number gives the number of protons. Protons which have a positive charge are balanced by an equal number of electrons in a neutral atom. Boron number 5 has five protons and therefore as a neutral atom also has five electrons.