**Answer:**

<em>mg</em>

**Explanation:**

**The only force which acts on the ball is its weight ( ****) once it is thrown. **

**The weight acts downwards. **

When the stone is thrown up, the final velocity at the maximum height is zero.

Initial velocity can be found by using law of conservation of energy.

Kinetic energy at the bottom = potential energy at the top

0.5 m v² = mgh

Answer:

1. Letter A indicates the crest.

2. Letter E indicates the wavelength.

3. Letter C indicates the trough.

Explanation:

1. Determination of the the crest.

A crest is simply defined as a point on a wave where the displacement is maximum (i.e highest).

Considering the diagram given above, the point where the displacement is maximum is A. Therefore, A is the crest of the wave.

2. Determination of the wavelength.

The wavelength of a wave is simply defined as the distance between two successive crest or trough.

Obeserving the diagram above, we can see that E gives the distance between two successive crest. Therefore, E is the wavelength of the wave.

3. Determination of the trough.

A trough is simply defined as a point on a wave where the displacement is minimum (i.e lowest). Thus we can say that the trough is the opposite of the crest.

Considering the diagram given above, the point where the displacement is minimum is C. Therefore, C is the trough of the wave.

**Answer:**

**a)**

**b) **

**Explanation:**

From the exercise we got final position, final velocity and how much time does it takes the body to cover the distance

From the concept of moving objects we know the following equations:

**and **

Now, we have two equations with two unknowns

**(1)**

Now, we need to replace **(1)** in the other equation

Solving for **a**

**b) **

Now, we can solve **(1)**

**a) **