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Helen [10]
3 years ago
8

Object is dropped from the top of a building that is 1125 m tall at the point when it’s speed is 30 m/s how far has it fallen

Physics
1 answer:
FrozenT [24]3 years ago
4 0

-- Gravity makes a falling object fall 9.8 m/s faster every second.

-- So, it reaches the speed of 30 m/s in (30/9.8) = 3.06 seconds after it's dropped.

-- The distance an object falls from rest is D = 1/2 (acceleration) (time)²

D = 1/2 (9.8 m/s²) (3.06 sec)²

D = (4.9 m/s²) (9.37 sec²)

<em>D = 45.8 meters</em>

Notice that we don't care how high the building is.  The problem works just as long as the object can reach 30 m/s before it hits the ground.  That  turns out to be anything higher than 45.8 meters for the drop . . . maybe something like 13 floors or more.

Now I'll go a little farther for you !  Writing the last paragraph made me a little curious and uncomfortable.  So I went and looked up the world's tallest buildings . . . and I found out that this problem could never happen !

The tallest building in the world now is the Burj Khalifa, in  Dubai.  It has 163 floors, and it's 828 meters high !  That's 2,717 feet.  It's gonna be a long time before there's a building that's 1125 meters tall, like this problem says.  That's close to 3700 feet . . . I've had flying lessons where I wasn't that far off the ground !

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A mass of 13kg stretches a spring 14cm. The mass is acted on by an external force of 6sin(t/2)N and moves in a medium that impar
m_a_m_a [10]

Answer:

13u\prime\prime+33.33u\prime+910u=6sin\frac{t}{2}, \ u(0)=0,u\prime(0)=0.04\\

#Where u is in meters and t in seconds.

Explanation:

Given that :m=13.0kg, \ L=0.14m, \ F(t)=6sin\frac{t}{2}N, F_d(t*)=-4N^{-1}, u\prime(t*)=0.12m/s\\u(0)=0,u\prime(0)=0.04m/s

From \omega=kL we have:

k=\frac{\omega}{L}=\frac{mg}{0.14m}=\frac{13.0\times 9.8m/s}{0.14m}\\\\k=910kg/s^2

From F_d(t)=-\gamma u\prime(t) we have that:

\gamma=-\frac{F_d(t*)}{u\prime(t*)}=\frac{4N}{0.12m/s}\\=33.33Ns/m

Now,given that the initial value problem is given by:

13u\prime\prime+33.33u\prime+910u=6sin\frac{t}{2}, \ u(0)=0,u\prime(0)=0.04\\

Hence,the position of u at time t is given by

13u\prime\prime+33.33u\prime+910u=6sin\frac{t}{2}, \ u(0)=0,u\prime(0)=0.04\\, u in meters,t in seconds.

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Light travels from medium X into medium Y. Medium Y has a higher index of refraction. Consider each statement below:(i) The ligh
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Answer:

i) FALSE,  ii) TRUE,  iii) FALSE, iv)  FALSE

Explanation:

When light (electromagnetic radiation) travels through a material medium, its speed is less than the speed of light in a vacuum. If we define the index of parts

           n = c / v

where v is the speed of light in the material medium.

The direction of the ray can be determined by the law of refraction

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Let's apply these equations to our case where

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therefore the expression is FALSE

ii) If we use the law of refraction, the light, when passing from a medium with a lower start to another with a higher index, must approach the normal one, away from what would be the continuation of the path of the incident ray

so the expression is TRUE

iii) The speed of light is constant in all material media

the statement is FALSE

iv) light approaches normal

Let me clarify that the normal is a line perpendicular to the surface at the point of contact, not the direction of Io.

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Answer:

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