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Gwar [14]
3 years ago
8

To measure the height of a building without a ruler or tape measure, an engineer drops a rock off the top of the building and fi

nds out it takes 4.9 seconds for the rock to reach the ground. How high is the building
Could you please tell me the steps, as well? I kind of understand how to do it, but some help would be greatly appreciated (:

Thanks.
Physics
1 answer:
serg [7]3 years ago
6 0

The relevant equation we can use in this problem is:

h = v0 t + 0.5 g t^2

where h is height, v0 is initial velocity, t is time, g is gravity

 

Since it was stated that the rock was drop, so it was free fall and v0 = 0, therefore:

h = 0 + 0.5 * 9.81 m/s^2 * (4.9 s)^2

<span>h = 117.77 m</span>

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A car starts from rest with an acceleration of 5.0 m / s² and travels a distance of 1.0 km. What is the speed value of this car?
Pepsi [2]

Answer:

100 m/s

Explanation:

We'll begin by converting 1 km to m. This can be obtained as follow:

1 km = 1000 m

Finally, we shall determine the final velocity of the car. This can be obtained as follow:

Initial velocity (u) = 0 m/s

Acceleration (a) = 5.0 m/s²

Distance (s) = 1000 m

Final velocity (v) =?

v² = u² + 2as

v² = 0² + (2 × 5 × 1000)

v² = 0 + 10000

v² = 10000

Take the square root of both side

v = √10000

v = 100 m/s

Therefore, the speed value of the car is 100 m/s.

5 0
3 years ago
What component of a longitudinal sound wave is analogous to a trough of a transverse wave?
anzhelika [568]

Explanation:

There are two components of a longitudinal sound wave which are compression and rarefaction. Similarly, there are two components of the transverse wave, the crest, and trough.

The crest of a wave is defined as the part that has a maximum value of displacement while the trough is defined as the part which corresponds to minimum displacement.

While compression is that space where the particles are close together while the rarefaction is that space where the particles are far apart from each other.

So, the refraction or the rarefied part of a longitudinal sound wave is analogous to a trough of a transverse wave.  

6 0
3 years ago
Melting, freezing, and boiling are _____________ changes. Question 3 options: A. compound
vfiekz [6]
Melting freezing and boiling are molecular changes


3 0
3 years ago
Read 2 more answers
What is population density?
Tpy6a [65]
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3 0
4 years ago
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If a ball is rolled down a frictionless inclined plane from a height of 3 feet, to what height would it roll up to on the other
mojhsa [17]

Answer:

It will roll up to its initial height from which it rolled from on the first hill

Explanation:

The given information are;

The height from which the ball is rolled = 3 feet[

The equation of the potential energy of the ball as it rolled down the frictionless inclined plane is given by the following equation;

m × g × h₁ = 1/2 × m × v² + 1/2×[2/5× m × r²) × [v/r]

Where;

m = The mass of the ball

h = The from which the ball is rolled down

v = The velocity of the ball

r = The radius of the ball

Therefore, all the potential energy, m × g × h, is converted into kinetic energy when the ball reached the ground

Similarly, as the ball rolls up on the other side, by the principle of energy conservation, all the kinetic energy is transformed into potential energy as follows

1/2 × m × v² + 1/2×[2/5× m × r²) × [v/r] = m × g × h₂, therefore, we have;

1/2 × m × v² + 1/2×[2/5× m × r²) × [v/r] = m × g × h₁ =  m × g × h₂

Therefore since m × g × h₁ =  m × g × h₂, then h₁ = h₂, the ball rises to the same height it started rolling from on the first hill.

3 0
3 years ago
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