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grin007 [14]
3 years ago
13

A ball is dropped off a roof. The ball falls for 4 seconds. Just before the ball hits the ground what is its velocity?

Physics
1 answer:
scZoUnD [109]3 years ago
7 0

Answer:

<em>The velocity is 39.24 m/s</em>

<em></em>

Explanation:

The time of fall t = 4 seconds

The initial velocity u = 0 m/s  (since the ball is dropped, meaning it starts from rest)

Final velocity v = ?

Using

v = u + gt

where g is the acceleration due to gravity = 9.81 m/s^2

substituting, we'll have

v = 0 + (9.81 x 4)

v = <em>39.24 m/s</em>

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#26 question
4vir4ik [10]

So, the time that taken for the astronaut to fall to the surface of the moon is <u>2.5 s.</u>

<h3>Introduction</h3>

Hi ! In this question, I will help you. In this question, you will learn about the fall time of the free fall motion. Free fall is a downward vertical motion without being preceded by an initial velocity. When moving in free fall, the time required can be calculated by the following equation:

\sf{h = \frac{1}{2} \cdot g \cdot t^2}

\sf{\frac{2 \cdot h}{g} = t^2}

\boxed{\sf{\bold{t = \sqrt{\frac{2 \cdot h}{g}}}}}

With the following condition :

  • t = interval of the time (s)
  • h = height or any other displacement at vertical line (m)
  • g = acceleration of the gravity (m/s²)

<h3>Problem Solving</h3>

We know that :

  • h = height = 5.00 m
  • g = acceleration of the gravity = 1.6 m/s²

What was asked :

  • t = interval of the time = ... s

Step by step :

\sf{t = \sqrt{\frac{2 \cdot h}{g}}}

\sf{t = \sqrt{\frac{2 \cdot 5}{1.6}}}

\sf{t = \sqrt{6.25}}

\boxed{\sf{t = 2.5 \: s}}

<h3>Conclusion</h3>

So, the time that taken for the astronaut to fall to the surface of the moon is 2.5 s.

<h3>See More</h3>
  • Time that needed for hearing the splash of fallen rock in the well brainly.com/question/26485521
  • The speed of the object at a certain height (free fall motion) brainly.com/question/26377041
  • The relationship between acceleration and the change in velocity and time in free fall brainly.com/question/26486625
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