Answer:

Ra, 88

Ru, 44

Cr, 24

Explanation:

i

the remaining mass number is 224(228 - 4), and it's atomic number is 88(90 - 2). The element is Radium, Ra

ii

the remaining mass number is 98(98 - 0), and it's atomic number is 44(45 - 1). The element is Ruthenium, Ru

iii

The remaining mass number is 52(52 - 0), and it's atomic number is 24(23 - -1). The element is Chromium, Cr

I am pretty sure it’s A

The cue exerts force onto the white ball which pushes the blue ball into the direction of the hole.

This is because they use less energy and also they seem to last longer.

**Answer:**

The doorknob

**Explanation:**

Hitting the door further out will cause greater magnitude than hitting it closer to where the door swings.

**Explanation:**

It is given that,

A ball hits the ground at 40 m/s

Let h is the height from where you drop a ball. It is based on the conservation of energy as :

It is dropped from a height of 81.63 m.

Let it take t seconds to hit the ground. When it hits the ground, its final speed, v = 0 and u = 40 m/s. So,

So, it will take 4.08 seconds to hit the ground.