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Semenov [28]
3 years ago
10

An Austin volleyball player bumps a 5 kg ball into the air. It reaches a height of 2.8 meters. How fast was the ball going as it

got bumped into the air?
O 137.2 m/s
O 7.4 m/s
O 19.6 m/s
O 14 m/s
Physics
1 answer:
KATRIN_1 [288]3 years ago
6 0

Answer:

v = 7.4 m/s

Explanation:

Given that,

Mass if a volleyball, m = 5 kg

The ball reaches a height of 2.8 m

We need to find how fast the ball is going as it bumped into the air. Ket the velocity is v. Using the conservation of energy to find it as follows :

mgh=\dfrac{1}{2}mv^2\\\\v=\sqrt{2gh} \\\\v=\sqrt{2\times 9.8\times 2.8} \\\\=7.4\ m/s

So, the required speed is 7.4 m/s. Hence, the correct option is (b).

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A player kicks a football from ground level with a velocity of 26.2m/s at an angle of 34.2° above the horizontal. How far back f
Amanda [17]

For the ball to go straight into the goal, the kicker needs to be no more than 6.54 meters away from the goal.

For the ball to arc into the goal, the kicker needs to be between 58.5 and 65.1 meters away from the goal.

<h3>Explanation</h3>

How long does it take for the ball to reach the goal?

Let the distance between the kicker and the goal be x meters.

Horizontal velocity of the ball will always be 26.2\times\cos{34.2\textdegree} until it lands if there's no air resistance.

The ball will arrive at the goal in \displaystyle \frac{x}{26.2\times\cos{34.2\textdegree}} seconds after it leaves the kicker.

What will be the height of the ball when it reaches the goal?

Consider the equation

\displaystyle h(t) = -\frac{1}{2}\cdot g\cdot t^{2} + v_{0,\;\text{vertical}} \cdot t + h_0.

For this soccer ball:

  • g = 9.81\;\text{m}\cdot\text{s}^{-2},
  • v_{0,\;\text{vertical}} = 26.2\times \sin{34.2\textdegree{}}\;\text{m}\cdot\text{s}^{-2},
  • h_0 = 0 since the player kicks the ball "from ground level."

\displaystyle t=\frac{x}{26.2\times\cos{34.2\textdegree}}

when the ball reaches the goal.

\displaystyle h= - 9.81 \times \frac{x^2}{(26.2\times\cos{34.2\textdegree})^2} + (26.2 \times \sin{34.2\textdegree})\times\frac{x}{26.2\times\cos{34.2\textdegree}} \\\phantom{h} = -\frac{9.81}{(26.2\times\cos{34.2\textdegree})^2}\cdot x^{2} + \frac{\sin{34.2\textdegree}}{\cos{34.2\textdegree}}\cdot x.

Solve this quadratic equation for x, x > 0.

  • x = 65.1 meters when h = 0 meters.
  • x = 6.54 or 58.5 meters when h = 4 meters.

In other words,

  • For the ball to go straight into the goal, the kicker needs to be no more than 6.54 meters away from the goal.
  • For the ball to arc into the goal, the kicker needs to be between 58.5 and 65.1 meters away from the goal.

3 0
3 years ago
Consider a wave along the length of a stretched slinky toy, where the distance between coils increases and decreases. What type
GrogVix [38]

Answer:

"Longitudinal wave" is the appropriate answer.

Explanation:

  • Generating waves whenever the form of communication being displaced in a similar direction as well as in the reverse way of the wave's designated points, could be determined as Longitudinal waves.
  • A wave running the length of something like a Slinky stuffed animal, which expands as well as reduces the spacing across spindles, produces a fine image or graphic.
3 0
3 years ago
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Why might it be important to know your inherited traits passed down by your parents?
ExtremeBDS [4]

Answer:

health factors that could harm you or your offspring

3 0
3 years ago
A cow wanders 30 m North, turns 22 degrees right of its original path, and wanders another 40 m. Find its total displacement.
scoundrel [369]

Answer:OB=58.3m

Explanation:

So here cow wanders 30m in north and turns 22 degrees in right side and moves 40m more, as shown in figure given.

now take the starting point as a origin such that cow moves in x-y co-ordinate axis.

As shown in figure length OA is the length when cow moves in north or y direction. Later she takes 22 degrees turn to right and moves 40m more.

So the final displacement is the length of cow from the origin that is length OB.

now co-ordinates of B are [40cos22°,40sin22°+30] i.e [37.084,44.984]

now displacement of cow= length of OB

                                           = \sqrt{[37.084]^{2}+[44.984]^{2}  }

                                           =\sqrt{3398.78}

                                     OB =58.3

                                         

7 0
1 year ago
PLEASE HELP!
Kobotan [32]

Answer:

No

Explanation:

Cause a monster truck don

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