Question

I need help on number six... I need to use the kinematics formula.

Answer 1

Given:

Height = 0.8 m

Initial velocity = 7.6 m/s

Given that the ball goes straight up, let's solve for the following.

(a) What will be the ball's velocity when it gets back to its original height.

Since the ball has an initial velocity of 7.6 m/s, the ball's velocity when it gets back to its original height will be the opposite of the initial velocity.

Here, the final velocity will be the same as the initial velocity but in the downward direction.

Therefore, the ball's velocity when it gets back to its original height will be -7.6 m/s

(b) How long will it take the volleyball to get to the top of its path.

To find how long it will take the volleyball to get to the top of its path, apply the formula:

`v^2_f=v^2_i+2ad`

Where:

vf is the final velocity at its maximum height = 0 m/s

vi is the initial velocity = 7.6 m/s

a is acceleration due to gravity = -9.8 m/s^2

d is the displacement

Let's solve for the displacement.

We have:

`\begin{gathered} d=(v^2_f-v^2_i)/(2a) \\ \\ d=(0^2-7.6^2)/(2(-9.8)) \\ \\ d=2.95\text{ m} \end{gathered}`

Now, to find the time it will take, apply the formula:

`v_f=v_i+at`

Where t is the time.

We have:

`\begin{gathered} 0=7.6+(-9.8)t \\ \\ t=(-7.6)/(-9.8) \\ \\ t=0.78s \end{gathered}`

ANSWER:

(a) -7.6 m/s

(b) 0.78 s